diff --git a/src/coreclr/jit/emitfmtswasm.h b/src/coreclr/jit/emitfmtswasm.h
index 55b852649192f5..f752369ae14b35 100644
--- a/src/coreclr/jit/emitfmtswasm.h
+++ b/src/coreclr/jit/emitfmtswasm.h
@@ -36,6 +36,7 @@ IF_DEF(F32,         IS_NONE, NONE) // <opcode> <f32 immediate (stored as 64-bit
 IF_DEF(F64,         IS_NONE, NONE) // <opcode> <f64 immediate (stored as 64-bit integer constant)>
 IF_DEF(MEMARG,      IS_NONE, NONE) // <opcode> <memarg> (<align> <offset>)
 IF_DEF(LOCAL_DECL,  IS_NONE, NONE) // <ULEB128 immediate> <byte>
+IF_DEF(MEMCPY,      IS_NONE, NONE) // <memory index> <memory index>
 
 #undef IF_DEF
 #endif // !DEFINE_ID_OPS
diff --git a/src/coreclr/jit/emitwasm.cpp b/src/coreclr/jit/emitwasm.cpp
index 8d08ab6a9bd826..9b3bec1e483cb7 100644
--- a/src/coreclr/jit/emitwasm.cpp
+++ b/src/coreclr/jit/emitwasm.cpp
@@ -319,6 +319,11 @@ unsigned emitter::instrDesc::idCodeSize() const
             size += idIsCnsReloc() ? PADDED_RELOC_SIZE : SizeOfULEB128(emitGetInsSC(this));
             break;
         }
+        case IF_MEMCPY:
+        {
+            size += idIsCnsReloc() ? PADDED_RELOC_SIZE : SizeOfULEB128(emitGetInsSC(this));
+            size += idIsCnsReloc() ? PADDED_RELOC_SIZE : SizeOfULEB128(emitGetInsSC(this));
+        }
         default:
             unreached();
     }
@@ -481,6 +486,14 @@ size_t emitter::emitOutputInstr(insGroup* ig, instrDesc* id, BYTE** dp)
             dst += emitOutputByte(dst, valType);
             break;
         }
+        case IF_MEMCPY:
+        {
+            dst += emitOutputOpcode(dst, ins);
+            cnsval_ssize_t constant = emitGetInsSC(id);
+            dst += emitOutputULEB128(dst, (uint64_t)constant);
+            dst += emitOutputULEB128(dst, (uint64_t)constant);
+            break;
+        }
         default:
             NYI_WASM("emitOutputInstr");
             break;
@@ -606,6 +619,13 @@ void emitter::emitDispIns(
         }
         break;
 
+        case IF_MEMCPY:
+        {
+            cnsval_ssize_t imm = emitGetInsSC(id);
+            printf(" %llu %llu", (uint64_t)imm, (uint64_t)imm);
+            dispJumpTargetIfAny();
+        }
+
         case IF_LOCAL_DECL:
         {
             unsigned int  count   = emitGetLclVarDeclCount(id);
diff --git a/src/coreclr/jit/instrswasm.h b/src/coreclr/jit/instrswasm.h
index 7230e20a64bf7e..70e870c1c55d8f 100644
--- a/src/coreclr/jit/instrswasm.h
+++ b/src/coreclr/jit/instrswasm.h
@@ -218,6 +218,10 @@ INST(i64_trunc_sat_f32_u, "i64.trunc_sat_f32_u", 0, IF_OPCODE,  0x05FC)
 INST(i64_trunc_sat_f64_s, "i64.trunc_sat_f64_s", 0, IF_OPCODE,  0x06FC)
 INST(i64_trunc_sat_f64_u, "i64.trunc_sat_f64_u", 0, IF_OPCODE,  0x07FC)
 
+INST(memory_copy,         "memory.copy",         0, IF_MEMCPY,  0x10FC)
+INST(memory_fill,         "memory.fill",         0, IF_ULEB128, 0x11FC)
+
+
 // clang-format on
 
 #undef INST
diff --git a/src/coreclr/jit/lowerwasm.cpp b/src/coreclr/jit/lowerwasm.cpp
index c7a8d34a437c24..7f93fa505e02c3 100644
--- a/src/coreclr/jit/lowerwasm.cpp
+++ b/src/coreclr/jit/lowerwasm.cpp
@@ -171,7 +171,62 @@ GenTree* Lowering::LowerBinaryArithmetic(GenTreeOp* binOp)
 //
 void Lowering::LowerBlockStore(GenTreeBlk* blkNode)
 {
-    NYI_WASM("LowerBlockStore");
+    GenTree* dstAddr = blkNode->Addr();
+    GenTree* src     = blkNode->Data();
+    unsigned size    = blkNode->Size();
+
+    if (blkNode->OperIsInitBlkOp())
+    {
+        if (src->OperIs(GT_INIT_VAL))
+        {
+            src->SetContained();
+            src = src->AsUnOp()->gtGetOp1();
+        }
+
+        if (blkNode->IsZeroingGcPointersOnHeap())
+        {
+            blkNode->gtBlkOpKind = GenTreeBlk::BlkOpKindLoop;
+            src->SetContained();
+        }
+        else
+        {
+            // memory.fill
+        }
+    }
+    else
+    {
+        assert(src->OperIs(GT_IND, GT_LCL_VAR, GT_LCL_FLD));
+        src->SetContained();
+
+        if (src->OperIs(GT_LCL_VAR))
+        {
+            // TODO-1stClassStructs: for now we can't work with STORE_BLOCK source in register.
+            // TODO-WASM: Is this true for wasm as well?
+            const unsigned srcLclNum = src->AsLclVar()->GetLclNum();
+            comp->lvaSetVarDoNotEnregister(srcLclNum DEBUGARG(DoNotEnregisterReason::BlockOp));
+        }
+
+        ClassLayout* layout               = blkNode->GetLayout();
+        bool         doCpObj              = layout->HasGCPtr();
+
+        // CopyObj or CopyBlk
+        if (doCpObj)
+        {
+            // Try to use bulk copy helper
+            if (TryLowerBlockStoreAsGcBulkCopyCall(blkNode))
+            {
+                return;
+            }
+
+            assert(dstAddr->TypeIs(TYP_BYREF, TYP_I_IMPL));
+            blkNode->gtBlkOpKind = GenTreeBlk::BlkOpKindCpObjUnroll;
+        }
+        else
+        {
+            assert(blkNode->OperIs(GT_STORE_BLK));
+            // memory.copy
+        }
+    }
 }
 
 //------------------------------------------------------------------------