diff --git a/eth/tracers/logger/logger.go b/eth/tracers/logger/logger.go
index 755b032ebc..719d91e80d 100644
--- a/eth/tracers/logger/logger.go
+++ b/eth/tracers/logger/logger.go
@@ -464,14 +464,14 @@ func formatLogs(logs []StructLog) []StructLogRes {
 		if trace.Memory != nil {
 			memory := make([]string, 0, (len(trace.Memory)+31)/32)
 			for i := 0; i+32 <= len(trace.Memory); i += 32 {
-				memory = append(memory, fmt.Sprintf("%x", trace.Memory[i:i+32]))
+				memory = append(memory, hexutil.Encode(trace.Memory[i:i+32]))
 			}
 			formatted[index].Memory = memory
 		}
 		if trace.Storage != nil {
-			storage := make(map[string]string)
+			storage := make(map[string]string, len(trace.Storage))
 			for i, storageValue := range trace.Storage {
-				storage[fmt.Sprintf("%x", i)] = fmt.Sprintf("%x", storageValue)
+				storage[fmt.Sprintf("%x", i)] = storageValue.Hex()
 			}
 			formatted[index].Storage = storage
 		}