diff --git a/Cargo.toml b/Cargo.toml
index 56b4a06..fefa2f1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,6 +16,7 @@ libc = "0.2"
 rand = "0.6"
 cfg-if = "0.1.9"
 log = "0.4"
+filetime = "0.2.6"
 
 [target.'cfg(unix)'.dependencies]
 nix = "0.13"
diff --git a/src/hostcalls_impl/fs.rs b/src/hostcalls_impl/fs.rs
index 4c677ca..577ac45 100644
--- a/src/hostcalls_impl/fs.rs
+++ b/src/hostcalls_impl/fs.rs
@@ -4,8 +4,10 @@ use crate::fdentry::{Descriptor, FdEntry};
 use crate::memory::*;
 use crate::sys::{errno_from_ioerror, host_impl, hostcalls_impl};
 use crate::{host, wasm32, Result};
+use filetime::{set_file_handle_times, FileTime};
 use log::trace;
 use std::io::{self, Read, Seek, SeekFrom, Write};
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
 pub(crate) fn fd_close(wasi_ctx: &mut WasiCtx, fd: wasm32::__wasi_fd_t) -> Result<()> {
     trace!("fd_close(fd={:?})", fd);
@@ -750,7 +752,34 @@ pub(crate) fn fd_filestat_set_times(
     let st_mtim = dec_timestamp(st_mtim);
     let fst_flags = dec_fstflags(fst_flags);
 
-    hostcalls_impl::fd_filestat_set_times(fd, st_atim, st_mtim, fst_flags)
+    let set_atim = fst_flags & host::__WASI_FILESTAT_SET_MTIM != 0;
+    let set_atim_now = fst_flags & host::__WASI_FILESTAT_SET_MTIM != 0;
+    let set_mtim = fst_flags & host::__WASI_FILESTAT_SET_MTIM != 0;
+    let set_mtim_now = fst_flags & host::__WASI_FILESTAT_SET_MTIM != 0;
+
+    if (set_atim && set_atim_now) || (set_mtim && set_mtim_now) {
+        return Err(host::__WASI_EINVAL);
+    }
+    let atim = if set_atim {
+        let time = UNIX_EPOCH + Duration::from_nanos(st_atim);
+        Some(FileTime::from_system_time(time))
+    } else if set_atim_now {
+        let time = SystemTime::now();
+        Some(FileTime::from_system_time(time))
+    } else {
+        None
+    };
+
+    let mtim = if set_mtim {
+        let time = UNIX_EPOCH + Duration::from_nanos(st_mtim);
+        Some(FileTime::from_system_time(time))
+    } else if set_mtim_now {
+        let time = SystemTime::now();
+        Some(FileTime::from_system_time(time))
+    } else {
+        None
+    };
+    set_file_handle_times(fd, atim, mtim).map_err(errno_from_ioerror)
 }
 
 pub(crate) fn fd_filestat_set_size(
diff --git a/src/sys/unix/hostcalls_impl/fs.rs b/src/sys/unix/hostcalls_impl/fs.rs
index 9f23e6d..f6feedd 100644
--- a/src/sys/unix/hostcalls_impl/fs.rs
+++ b/src/sys/unix/hostcalls_impl/fs.rs
@@ -406,49 +406,6 @@ fn filetype(metadata: &Metadata) -> host::__wasi_filetype_t {
     }
 }
 
-pub(crate) fn fd_filestat_set_times(
-    fd: &File,
-    st_atim: host::__wasi_timestamp_t,
-    mut st_mtim: host::__wasi_timestamp_t,
-    fst_flags: host::__wasi_fstflags_t,
-) -> Result<()> {
-    use nix::sys::time::{TimeSpec, TimeValLike};
-
-    if fst_flags & host::__WASI_FILESTAT_SET_MTIM_NOW != 0 {
-        let clock_id = libc::CLOCK_REALTIME;
-        let mut timespec = unsafe { std::mem::uninitialized::<libc::timespec>() };
-        let res = unsafe { libc::clock_gettime(clock_id, &mut timespec as *mut libc::timespec) };
-        if res != 0 {
-            return Err(host_impl::errno_from_nix(nix::errno::Errno::last()));
-        }
-        st_mtim = (timespec.tv_sec as host::__wasi_timestamp_t)
-            .checked_mul(1_000_000_000)
-            .and_then(|sec_ns| sec_ns.checked_add(timespec.tv_nsec as host::__wasi_timestamp_t))
-            .ok_or(host::__WASI_EOVERFLOW)?;
-    }
-    let ts_atime = match fst_flags {
-        f if f & host::__WASI_FILESTAT_SET_ATIM_NOW != 0 => libc::timespec {
-            tv_sec: 0,
-            tv_nsec: utime_now(),
-        },
-        f if f & host::__WASI_FILESTAT_SET_ATIM != 0 => {
-            *TimeSpec::nanoseconds(st_atim as i64).as_ref()
-        }
-        _ => libc::timespec {
-            tv_sec: 0,
-            tv_nsec: utime_omit(),
-        },
-    };
-    let ts_mtime = *TimeSpec::nanoseconds(st_mtim as i64).as_ref();
-    let times = [ts_atime, ts_mtime];
-    let res = unsafe { libc::futimens(fd.as_raw_fd(), times.as_ptr()) };
-    if res != 0 {
-        Err(host_impl::errno_from_nix(nix::errno::Errno::last()))
-    } else {
-        Ok(())
-    }
-}
-
 pub(crate) fn fd_filestat_set_size(fd: &File, st_size: host::__wasi_filesize_t) -> Result<()> {
     use nix::unistd::ftruncate;
     ftruncate(fd.as_raw_fd(), st_size as off_t)
diff --git a/src/sys/windows/hostcalls_impl/fs.rs b/src/sys/windows/hostcalls_impl/fs.rs
index ef55639..288b7a1 100644
--- a/src/sys/windows/hostcalls_impl/fs.rs
+++ b/src/sys/windows/hostcalls_impl/fs.rs
@@ -234,15 +234,6 @@ fn filetype(metadata: &Metadata) -> io::Result<host::__wasi_filetype_t> {
     Ok(ret)
 }
 
-pub(crate) fn fd_filestat_set_times(
-    fd: &File,
-    st_atim: host::__wasi_timestamp_t,
-    mut st_mtim: host::__wasi_timestamp_t,
-    fst_flags: host::__wasi_fstflags_t,
-) -> Result<()> {
-    unimplemented!("fd_filestat_set_times")
-}
-
 pub(crate) fn fd_filestat_set_size(fd: &File, st_size: host::__wasi_filesize_t) -> Result<()> {
     unimplemented!("fd_filestat_set_size")
 }