diff --git a/drools-model/drools-model-compiler/src/test/java/org/drools/modelcompiler/bigdecimaltest/BigDecimalTest.java b/drools-model/drools-model-compiler/src/test/java/org/drools/modelcompiler/bigdecimaltest/BigDecimalTest.java
index 9f011cf353a..8c23ef59a58 100644
--- a/drools-model/drools-model-compiler/src/test/java/org/drools/modelcompiler/bigdecimaltest/BigDecimalTest.java
+++ b/drools-model/drools-model-compiler/src/test/java/org/drools/modelcompiler/bigdecimaltest/BigDecimalTest.java
@@ -492,4 +492,29 @@ public void testBigDecimalLiteralWithBinding() {
 
         Assertions.assertThat(result).containsExactly(new BigDecimal("0"));
     }
+
+    @Test
+    public void testModifyWithNegativeBigDecimal() {
+        // DROOLS-7324
+        String str =
+                "package org.drools.modelcompiler.bigdecimals\n" +
+                "import " + BdHolder.class.getCanonicalName() + ";\n" +
+                "global java.util.List result;\n" +
+                "rule R1 dialect \"mvel\" when\n" +
+                "    $bd : BdHolder(bd1 > 5)\n" +
+                "then\n" +
+                "    modify($bd) { bd1 = -1 }\n" +
+                "end";
+
+        KieSession ksession = getKieSession(str);
+        List<BigDecimal> result = new ArrayList<>();
+        ksession.setGlobal("result", result);
+
+        BdHolder holder = new BdHolder();
+        holder.setBd1(new BigDecimal("10"));
+        ksession.insert(holder);
+        int fires = ksession.fireAllRules();
+
+        assertThat(fires).isEqualTo(1);
+    }
 }
diff --git a/drools-model/drools-mvel-compiler/src/main/java/org/drools/mvelcompiler/ReProcessRHSPhase.java b/drools-model/drools-mvel-compiler/src/main/java/org/drools/mvelcompiler/ReProcessRHSPhase.java
index 63f8fd8b14b..d036af6e30e 100644
--- a/drools-model/drools-mvel-compiler/src/main/java/org/drools/mvelcompiler/ReProcessRHSPhase.java
+++ b/drools-model/drools-mvel-compiler/src/main/java/org/drools/mvelcompiler/ReProcessRHSPhase.java
@@ -25,6 +25,7 @@
 import com.github.javaparser.ast.expr.IntegerLiteralExpr;
 import com.github.javaparser.ast.expr.LongLiteralExpr;
 import com.github.javaparser.ast.expr.NameExpr;
+import com.github.javaparser.ast.expr.UnaryExpr;
 import org.drools.mvel.parser.ast.visitor.DrlGenericVisitor;
 import org.drools.mvelcompiler.ast.BigDecimalConvertedExprT;
 import org.drools.mvelcompiler.ast.IntegerLiteralExpressionT;
@@ -36,55 +37,73 @@
 /**
  * Used when you need to reprocess the RHS after having processed the LHS
  */
-public class ReProcessRHSPhase implements DrlGenericVisitor<Optional<TypedExpression>, Void> {
+public class ReProcessRHSPhase implements DrlGenericVisitor<Optional<TypedExpression>, ReProcessRHSPhase.Context> {
 
     private TypedExpression lhs;
     private MvelCompilerContext mvelCompilerContext;
 
+    static class Context {
+        private UnaryExpr unaryExpr;
+
+        Context withUnaryExpr(UnaryExpr unaryExpr) {
+            this.unaryExpr = unaryExpr;
+            return this;
+        }
+
+        Optional<UnaryExpr> getUnaryExpr() {
+            return Optional.ofNullable(unaryExpr);
+        }
+    }
+
     ReProcessRHSPhase(MvelCompilerContext mvelCompilerContext) {
         this.mvelCompilerContext = mvelCompilerContext;
     }
 
     public Optional<TypedExpression> invoke(TypedExpression rhs, TypedExpression lhs) {
         this.lhs = lhs;
-        return Optional.ofNullable(rhs).flatMap(r -> r.toJavaExpression().accept(this, null));
+        return Optional.ofNullable(rhs).flatMap(r -> r.toJavaExpression().accept(this, new Context()));
     }
 
     @Override
-    public Optional<TypedExpression> defaultMethod(Node n, Void context) {
+    public Optional<TypedExpression> defaultMethod(Node n, ReProcessRHSPhase.Context context) {
         return Optional.empty();
     }
 
     @Override
-    public Optional<TypedExpression> visit(BinaryExpr n, Void arg) {
-        return convertWhenLHSISBigDecimal(() -> new UnalteredTypedExpression(n));
+    public Optional<TypedExpression> visit(UnaryExpr n, ReProcessRHSPhase.Context context) {
+        return n.getExpression().accept(this, context.withUnaryExpr(n));
+    }
+
+    @Override
+    public Optional<TypedExpression> visit(BinaryExpr n, ReProcessRHSPhase.Context context) {
+        return convertWhenLHSISBigDecimal(() -> new UnalteredTypedExpression(n), context);
     }
 
     @Override
-    public Optional<TypedExpression> visit(IntegerLiteralExpr n, Void arg) {
-        return convertWhenLHSISBigDecimal(() -> new IntegerLiteralExpressionT(n));
+    public Optional<TypedExpression> visit(IntegerLiteralExpr n, ReProcessRHSPhase.Context context) {
+        return convertWhenLHSISBigDecimal(() -> new IntegerLiteralExpressionT(n), context);
     }
 
     @Override
-    public Optional<TypedExpression> visit(LongLiteralExpr n, Void arg) {
-        return convertWhenLHSISBigDecimal(() -> new LongLiteralExpressionT(n));
+    public Optional<TypedExpression> visit(LongLiteralExpr n, ReProcessRHSPhase.Context context) {
+        return convertWhenLHSISBigDecimal(() -> new LongLiteralExpressionT(n), context);
     }
 
     @Override
-    public Optional<TypedExpression> visit(NameExpr n, Void arg) {
+    public Optional<TypedExpression> visit(NameExpr n, ReProcessRHSPhase.Context context) {
         if(mvelCompilerContext
                 .findDeclarations(n.toString())
                 .filter(d -> d.getClazz() != BigDecimal.class)
                 .isPresent()) { // avoid wrapping BigDecimal declarations
-            return convertWhenLHSISBigDecimal(() -> new UnalteredTypedExpression(n));
+            return convertWhenLHSISBigDecimal(() -> new UnalteredTypedExpression(n), context);
         } else {
             return Optional.empty();
         }
     }
 
-    private Optional<TypedExpression> convertWhenLHSISBigDecimal(Supplier<TypedExpression> conversionFunction) {
+    private Optional<TypedExpression> convertWhenLHSISBigDecimal(Supplier<TypedExpression> conversionFunction, ReProcessRHSPhase.Context context) {
         return lhs.getType()
                 .filter(BigDecimal.class::equals)
-                .flatMap(t -> Optional.of(new BigDecimalConvertedExprT(conversionFunction.get())));
+                .flatMap(t -> Optional.of(new BigDecimalConvertedExprT(conversionFunction.get(), context.getUnaryExpr())));
     }
 }
diff --git a/drools-model/drools-mvel-compiler/src/main/java/org/drools/mvelcompiler/ast/BigDecimalConvertedExprT.java b/drools-model/drools-mvel-compiler/src/main/java/org/drools/mvelcompiler/ast/BigDecimalConvertedExprT.java
index 733e36f0a1f..057d09701dc 100644
--- a/drools-model/drools-mvel-compiler/src/main/java/org/drools/mvelcompiler/ast/BigDecimalConvertedExprT.java
+++ b/drools-model/drools-mvel-compiler/src/main/java/org/drools/mvelcompiler/ast/BigDecimalConvertedExprT.java
@@ -24,6 +24,7 @@
 import com.github.javaparser.ast.Node;
 import com.github.javaparser.ast.expr.Expression;
 import com.github.javaparser.ast.expr.ObjectCreationExpr;
+import com.github.javaparser.ast.expr.UnaryExpr;
 
 import static com.github.javaparser.ast.NodeList.nodeList;
 
@@ -32,8 +33,15 @@ public class BigDecimalConvertedExprT implements TypedExpression {
     private final TypedExpression value;
     private final Type type = BigDecimal.class;
 
+    private final Optional<UnaryExpr> unaryExpr;
+
     public BigDecimalConvertedExprT(TypedExpression value) {
+        this(value, Optional.empty());
+    }
+
+    public BigDecimalConvertedExprT(TypedExpression value, Optional<UnaryExpr> unaryExpr) {
         this.value = value;
+        this.unaryExpr = unaryExpr;
     }
 
     @Override
@@ -43,10 +51,9 @@ public Optional<Type> getType() {
 
     @Override
     public Node toJavaExpression() {
-
-        return new ObjectCreationExpr(null,
-                                      StaticJavaParser.parseClassOrInterfaceType(type.getTypeName()),
-                                      nodeList((Expression) value.toJavaExpression()));
+        Expression expr = (Expression) value.toJavaExpression();
+        Expression arg = unaryExpr.map(u -> (Expression) new UnaryExpr(expr, u.getOperator())).orElse(expr);
+        return new ObjectCreationExpr(null, StaticJavaParser.parseClassOrInterfaceType(type.getTypeName()), nodeList(arg));
     }
 
     @Override