diff --git a/lib/compiler.c b/lib/compiler.c
index bc209f3..95099ba 100644
--- a/lib/compiler.c
+++ b/lib/compiler.c
@@ -121,6 +121,17 @@ void compiler_run(compiler_t* compiler, node_t* node)
           {
             op = OP_USUB;
           }
+        else if (node->type == NODE_ADD
+                 && node_find_first(node, NODE_STR))
+          {
+            op = OP_STRCAT;
+          }
+        else if (node->type == NODE_MUL
+                 && node_find_first(node, NODE_STR)
+                 && node_find_first(node, NODE_NUM))
+          {
+            op = OP_STRDUP;
+          }
         else
           {
             switch (node->type)
diff --git a/lib/node.c b/lib/node.c
index 2190479..66aed2b 100644
--- a/lib/node.c
+++ b/lib/node.c
@@ -97,3 +97,25 @@ size_t node_str(node_t* node, char* buffer, size_t size)
 
   return sz;
 }
+
+node_t* node_find_first(node_t* node, NodeType type)
+{
+  assert(node);
+
+  if (node->type == type)
+    {
+      return node;
+    }
+
+  for (size_t i=0; i<node->children.size; i++)
+    {
+      node_t* child = node_find_first((node_t*) node->children.data[i], type);
+
+      if (child)
+        {
+          return child;
+        }
+    }
+
+  return NULL;
+}
diff --git a/lib/node.h b/lib/node.h
index 6b0efc8..f045312 100644
--- a/lib/node.h
+++ b/lib/node.h
@@ -34,5 +34,6 @@ void node_add_new_child(node_t* node, node_t* child);
 node_t* node_child(node_t* node, size_t index);
 
 size_t node_str(node_t* node, char* buffer, size_t size);
+node_t* node_find_first(node_t* node, NodeType type);
 
 #endif
diff --git a/lib/opcodes.h b/lib/opcodes.h
index a83c2e2..62c0c99 100644
--- a/lib/opcodes.h
+++ b/lib/opcodes.h
@@ -11,7 +11,8 @@
     G(OP_ADD), G(OP_SUB), G(OP_MUL), G(OP_DIV), \
     G(OP_MODULO), G(OP_POW), G(OP_USUB),        \
     G(OP_AND), G(OP_OR), G(OP_NOT),             \
-    G(OP_BRF), G(OP_BRT), G(OP_BR)
+    G(OP_BRF), G(OP_BRT), G(OP_BR),             \
+    G(OP_STRCAT), G(OP_STRDUP)
 
 
 RZ_ENUM_H(Opcode, OPCODES);
diff --git a/lib/vm.c b/lib/vm.c
index 5c6ecae..fb4f0e0 100644
--- a/lib/vm.c
+++ b/lib/vm.c
@@ -21,7 +21,7 @@ void vm_free(vm_t* vm)
   assert(vm);
 }
 
-void vm_push_value(vm_t* vm, mod_t* mod, value_t* value)
+void vm_push_new_value(vm_t* vm, mod_t* mod, value_t* value)
 {
   assert(vm);
   assert(value);
@@ -146,7 +146,7 @@ int vm_exec_instr(vm_t* vm, mod_t* mod, Opcode op, param_t param)
                                     : (!same_type || !eq)),
                                    rhs->line);
 
-      vm_push_value(vm, mod, res);
+      vm_push_new_value(vm, mod, res);
 
       vm->pc++;
     } break;
@@ -176,7 +176,7 @@ int vm_exec_instr(vm_t* vm, mod_t* mod, Opcode op, param_t param)
         }
 
       value_t* res = tysy_new_bool(vm->tysy, val, lhs->line);
-      vm_push_value(vm, mod, res);
+      vm_push_new_value(vm, mod, res);
 
       vm->pc++;
     } break;
@@ -210,7 +210,63 @@ int vm_exec_instr(vm_t* vm, mod_t* mod, Opcode op, param_t param)
         }
 
       value_t* res = tysy_new_num(vm->tysy, val, lhs->line);
-      vm_push_value(vm, mod, res);
+      vm_push_new_value(vm, mod, res);
+
+      vm->pc++;
+    } break;
+
+    case OP_STRCAT: {
+      int r = vm_pop(vm);
+      int l = vm_pop(vm);
+
+      value_t* lhs = mod->values.data[l];
+      value_t* rhs = mod->values.data[r];
+
+      vm_ensure_type(vm, lhs, TYPE_STR);
+      vm_ensure_type(vm, rhs, TYPE_STR);
+
+      str_t res;
+      str_init(&res);
+      str_append(&res, lhs->value.str);
+      str_append(&res, rhs->value.str);
+
+      value_t* value = tysy_new_str(vm->tysy, res.data, lhs->line);
+      str_free(&res);
+
+      vm_push_new_value(vm, mod, value);
+
+      vm->pc++;
+    } break;
+
+    case OP_STRDUP: {
+      int r = vm_pop(vm);
+      int l = vm_pop(vm);
+
+      value_t* lhs = mod->values.data[l];
+      value_t* rhs = mod->values.data[r];
+
+      if (lhs->type->kind != TYPE_NUM)
+        {
+          value_t* tmp = lhs;
+          lhs = rhs;
+          rhs = tmp;
+        }
+
+      vm_ensure_type(vm, lhs, TYPE_NUM);
+      vm_ensure_type(vm, rhs, TYPE_STR);
+
+      str_t res;
+      str_init(&res);
+
+      for (int i=0; i<(int) lhs->value.num; i++)
+        {
+          str_append(&res, rhs->value.str);
+        }
+
+      value_t* value = tysy_new_str(vm->tysy, res.data, lhs->line);
+      str_free(&res);
+
+      vm_push_new_value(vm, mod, value);
 
       vm->pc++;
     } break;
@@ -236,7 +292,7 @@ int vm_exec_instr(vm_t* vm, mod_t* mod, Opcode op, param_t param)
         }
 
       value_t* res = tysy_new_bool(vm->tysy, val, lhs->line);
-      vm_push_value(vm, mod, res);
+      vm_push_new_value(vm, mod, res);
 
       vm->pc++;
     } break;
@@ -251,7 +307,7 @@ int vm_exec_instr(vm_t* vm, mod_t* mod, Opcode op, param_t param)
       double val = -lhs->value.num;
 
       value_t* res = tysy_new_num(vm->tysy, val, lhs->line);
-      vm_push_value(vm, mod, res);
+      vm_push_new_value(vm, mod, res);
 
       vm->pc++;
     } break;
@@ -264,7 +320,7 @@ int vm_exec_instr(vm_t* vm, mod_t* mod, Opcode op, param_t param)
       int val = !lhs->value.bool;
 
       value_t* res = tysy_new_bool(vm->tysy, val, lhs->line);
-      vm_push_value(vm, mod, res);
+      vm_push_new_value(vm, mod, res);
 
       vm->pc++;
     } break;
@@ -320,5 +376,6 @@ void vm_ensure_type(vm_t* vm, value_t* value, TypeKind want)
                TypeKindStr[got] + strlen("TYPE_"));
 
       err_fatal(vm->err, msg, line);
+      err_dump(vm->err);
     }
 }
diff --git a/lib/vm.h b/lib/vm.h
index 9745e9a..6292b39 100644
--- a/lib/vm.h
+++ b/lib/vm.h
@@ -20,7 +20,7 @@ typedef struct {
 void vm_init(vm_t* vm, tysy_t* tysy, err_t* err);
 void vm_free(vm_t* vm);
 
-void vm_push_value(vm_t* vm, mod_t* mod, value_t* value);
+void vm_push_new_value(vm_t* vm, mod_t* mod, value_t* value);
 void vm_push(vm_t* vm, param_t param);
 param_t vm_pop(vm_t* vm);
 
diff --git a/tests/acceptances/str.roza b/tests/acceptances/str.roza
new file mode 100644
index 0000000..213d273
--- /dev/null
+++ b/tests/acceptances/str.roza
@@ -0,0 +1,14 @@
+# STRING OPERATIONS
+# =================
+
+# concatenation with +
+assert "hel" + "lo" == "hello"
+assert "hello" + " " + "world" == "hello world"
+
+# duplication with *
+assert "a" * 3 == "aaa"
+assert 4 * "!" == "!!!!"
+
+# bonus
+assert ("a" * 2) + "b" == "aab"
+assert 4 * ("a" + "b") == "abababab"
\ No newline at end of file
diff --git a/tests/units/lexer.c b/tests/units/lexer.c
index e4f8f13..9065688 100644
--- a/tests/units/lexer.c
+++ b/tests/units/lexer.c
@@ -152,5 +152,4 @@ Test(lexer, bool_arith) {
              "AND",
              "OR",
              "NOT");
-
 }