Abstract: Two modifications for Johnson's enzymatic method of preparation of α-32PdCTP are introduced as follows, (1) temperature of reaction in the second stage is controlled at 5-22℃; (2) nuclease P1 is eliminated from the procedure in the third stage. Owing to reduced temperature the final yield of the procedure reaches 90-97% relative to 32Pi. The product cost is reduced and the operating process is simplified as a result of eliminating nuclease P1.