diff --git a/src/string/src/lib.rs b/src/string/src/lib.rs
index 5b5c15832b..3fd95d0014 100644
--- a/src/string/src/lib.rs
+++ b/src/string/src/lib.rs
@@ -250,8 +250,13 @@ pub unsafe extern "C" fn strncpy(s1: *mut c_char, s2: *const c_char, n: usize) -
 }
 
 #[no_mangle]
-pub extern "C" fn strpbrk(s1: *const c_char, s2: *const c_char) -> *mut c_char {
-    unimplemented!();
+pub unsafe extern "C" fn strpbrk(s1: *const c_char, s2: *const c_char) -> *mut c_char {
+    let p = s1.offset(strcspn(s1, s2) as isize);
+    if *p != 0 {
+        p as *mut c_char
+    } else {
+        ptr::null_mut()
+    }
 }
 
 #[no_mangle]
@@ -299,8 +304,22 @@ pub unsafe extern "C" fn strspn(s1: *const c_char, s2: *const c_char) -> c_ulong
 }
 
 #[no_mangle]
-pub extern "C" fn strstr(s1: *const c_char, s2: *const c_char) -> *mut c_char {
-    unimplemented!();
+pub unsafe extern "C" fn strstr(s1: *const c_char, s2: *const c_char) -> *mut c_char {
+    let mut i = 0;
+    while *s1.offset(i) != 0 {
+        let mut j = 0;
+        while *s2.offset(j) != 0 && *s1.offset(j + i) != 0 {
+            if *s2.offset(j) != *s1.offset(j + i) {
+                break;
+            }
+            j += 1;
+            if *s2.offset(j) == 0 {
+                return s1.offset(i) as *mut c_char;
+            }
+        }
+        i += 1;
+    }
+    ptr::null_mut()
 }
 
 #[no_mangle]
diff --git a/tests/Makefile b/tests/Makefile
index a252889605..351d48df23 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -27,6 +27,8 @@ EXPECT_BINS=\
 	string/strchr \
 	string/strrchr \
 	string/strspn \
+	string/strstr \
+	string/strpbrk \
 	unlink \
 	write
 
diff --git a/tests/expected/string/strpbrk.stderr b/tests/expected/string/strpbrk.stderr
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/expected/string/strpbrk.stdout b/tests/expected/string/strpbrk.stdout
new file mode 100644
index 0000000000..7a6bc8b089
--- /dev/null
+++ b/tests/expected/string/strpbrk.stdout
@@ -0,0 +1,3 @@
+The quick drawn fix jumps over the lazy bug
+lazy bug
+NULL
diff --git a/tests/expected/string/strstr.stderr b/tests/expected/string/strstr.stderr
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/expected/string/strstr.stdout b/tests/expected/string/strstr.stdout
new file mode 100644
index 0000000000..e978edff7f
--- /dev/null
+++ b/tests/expected/string/strstr.stdout
@@ -0,0 +1,3 @@
+rust
+libc we trust
+NULL
diff --git a/tests/string/strpbrk.c b/tests/string/strpbrk.c
new file mode 100644
index 0000000000..dc0ebf7c53
--- /dev/null
+++ b/tests/string/strpbrk.c
@@ -0,0 +1,20 @@
+#include <string.h>
+#include <stdio.h>
+
+int main(int argc, char* argv[]) {
+    char* source = "The quick drawn fix jumps over the lazy bug";
+
+    // should be "The quick drawn fix jumps over the lazy bug"
+    char* res1 = strpbrk(source, "From The Very Beginning");
+    printf("%s\n", (res1) ? res1 : "NULL"); 
+
+    // should be "lazy bug"
+    char* res2 = strpbrk(source, "lzbg");
+    printf("%s\n", (res2) ? res2 : "NULL"); 
+
+    // should be "NULL"
+    char* res3 = strpbrk(source, "404");
+    printf("%s\n", (res3) ? res3 : "NULL"); 
+
+    return 0;
+}
diff --git a/tests/string/strstr.c b/tests/string/strstr.c
new file mode 100644
index 0000000000..6a074d18d8
--- /dev/null
+++ b/tests/string/strstr.c
@@ -0,0 +1,18 @@
+#include <string.h>
+#include <stdio.h>
+
+int main(int argc, char* argv[]) {
+    // should be "rust"
+    char* res1 = strstr("In relibc we trust", "rust");
+    printf("%s\n", (res1) ? res1 : "NULL"); 
+
+    // should be "libc we trust"
+    char* res2 = strstr("In relibc we trust", "libc");
+    printf("%s\n", (res2) ? res2 : "NULL"); 
+
+    // should be "NULL"
+    char* res3 = strstr("In relibc we trust", "bugs");
+    printf("%s\n", (res3) ? res3 : "NULL"); 
+
+    return 0;
+}