The study included the role of some plant growth regulators and their effect in Prosopis farcta explants response for initiation and growth of callus cultures and detection for caffiec acid in the callus cultures. Results showed that the best treatment for sterilization of Prosopis farcta seeds was treating the seeds with 96% ethanol for 2 min., then treating them with sodium hypochlorite diluted with distilled water )1 : 2) (water : sodium hypochlorite( (v : v) for 10 min. Results also showed that when Prosopis farcta seedling stem explants containing nodes were cultured on MS solidified medium containing 2.5 mg/l of BA and 0.5 mg/l of 2,4-D was the best to initiate and grow of callus depending on fresh weight of callus. This study included the detection of caffeic acid in callus cultures of Prosopis using Thin layer chromatography )TLC(. It was found that the Rf value of the standard sample is almost the same as that for the callus sample.it was concluded that callus cultures of Prosopis contain caffeic acid.