diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 3a91dde4de..9238fd0086 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -1229,6 +1229,13 @@ func (s *BlockChainAPI) Call(ctx context.Context, args TransactionArgs, blockNrO
 // Note, this function doesn't make any changes in the state/blockchain and is
 // useful to execute and retrieve values.
 func (s *BlockChainAPI) MulticallV1(ctx context.Context, opts multicallOpts, blockNrOrHash *rpc.BlockNumberOrHash) ([]blockResult, error) {
+	if len(opts.BlockStateCalls) == 0 {
+		// TODO return error code.
+		return nil, errors.New("invalid params")
+	} else if len(opts.BlockStateCalls) > maxMulticallBlocks {
+		// TODO return error code.
+		return nil, errors.New("invalid params")
+	}
 	if blockNrOrHash == nil {
 		n := rpc.BlockNumberOrHashWithNumber(rpc.LatestBlockNumber)
 		blockNrOrHash = &n
diff --git a/internal/ethapi/multicall.go b/internal/ethapi/multicall.go
index f6151f09fb..c3e20da04d 100644
--- a/internal/ethapi/multicall.go
+++ b/internal/ethapi/multicall.go
@@ -37,6 +37,12 @@ import (
 	"github.com/ethereum/go-ethereum/trie"
 )
 
+const (
+	// maxMulticallBlocks is the maximum number of blocks that can be simulated
+	// in a single request.
+	maxMulticallBlocks = 256
+)
+
 // CallBatch is a batch of calls to be simulated sequentially.
 type CallBatch struct {
 	BlockOverrides *BlockOverrides