diff --git a/apps/zasm/directive.asm b/apps/zasm/directive.asm
index 6c89efe..681366d 100644
--- a/apps/zasm/directive.asm
+++ b/apps/zasm/directive.asm
@@ -79,8 +79,10 @@ handleDW:
 	push	hl
 .loop:
 	call	readWord
+	jr	nz, .badfmt
 	ld	hl, scratchpad
 	call	parseExpr
+	jr	nz, .badarg
 	push	ix \ pop hl
 	ld	a, l
 	call	ioPutC
@@ -91,6 +93,15 @@ handleDW:
 	cp	a		; ensure Z
 	pop	hl
 	ret
+.badfmt:
+	ld	a, ERR_BAD_FMT
+	jr	.error
+.badarg:
+	ld	a, ERR_BAD_ARG
+.error:
+	call	unsetZ
+	pop	hl
+	ret
 
 handleEQU:
 	push	hl
diff --git a/tools/tests/zasm/errtests.sh b/tools/tests/zasm/errtests.sh
index fb7f7b2..6d178fe 100755
--- a/tools/tests/zasm/errtests.sh
+++ b/tools/tests/zasm/errtests.sh
@@ -20,8 +20,10 @@ chkerr "foo" 1
 chkerr "ld a, foo" 2
 chkerr "ld a, hl" 2
 chkerr ".db foo" 2
+chkerr ".dw foo" 2
 chkerr "ld a," 3
 chkerr "ld a, 'A" 3
 chkerr ".db 0x42," 3
+chkerr ".dw 0x4242," 3
 chkerr "ld a, 0x100" 4
 chkerr ".db 0x100" 4