diff --git a/node/_os.ts b/node/_os.ts
index 773cca8bdcbe..14bf20abd2ad 100644
--- a/node/_os.ts
+++ b/node/_os.ts
@@ -123,9 +123,9 @@ export function endianness(): "BE" | "LE" {
   return new Int16Array(buffer)[0] === 256 ? "LE" : "BE";
 }
 
-/** Not yet implemented */
+/** Return free memory amount */
 export function freemem(): number {
-  notImplemented(SEE_GITHUB_ISSUE);
+  return Deno.systemMemoryInfo().free;
 }
 
 /** Not yet implemented */
@@ -185,9 +185,9 @@ export function tmpdir(): string | null {
   notImplemented(SEE_GITHUB_ISSUE);
 }
 
-/** Not yet implemented */
+/** Return total physical memory amount */
 export function totalmem(): number {
-  notImplemented(SEE_GITHUB_ISSUE);
+  return Deno.systemMemoryInfo().total;
 }
 
 /** Not yet implemented */
diff --git a/node/os_test.ts b/node/os_test.ts
index e4231aa3cda5..8879f8345a10 100644
--- a/node/os_test.ts
+++ b/node/os_test.ts
@@ -200,6 +200,20 @@ Deno.test({
   },
 });
 
+Deno.test({
+  name: "Total memory amount should be greater than 0",
+  fn() {
+    assert(os.totalmem() > 0);
+  },
+});
+
+Deno.test({
+  name: "Free memory amount should be greater than 0",
+  fn() {
+    assert(os.freemem() > 0);
+  },
+});
+
 Deno.test({
   name: "APIs not yet implemented",
   fn() {
@@ -210,13 +224,6 @@ Deno.test({
       Error,
       "Not implemented",
     );
-    assertThrows(
-      () => {
-        os.freemem();
-      },
-      Error,
-      "Not implemented",
-    );
     assertThrows(
       () => {
         os.getPriority();
@@ -238,13 +245,6 @@ Deno.test({
       Error,
       "Not implemented",
     );
-    assertThrows(
-      () => {
-        os.totalmem();
-      },
-      Error,
-      "Not implemented",
-    );
     assertThrows(
       () => {
         os.type();