Comparative studies were made on the growth and biometric relationships of the pearl oyster Pinctada radiata, which is a candidate species for mariculture and pearl production in Egypt. A total of 613 oysters were collected from three stations along Egyptian Mediterranean coast, off Alexandria. The size structure of the sampled populations was described and the relative growth parameters were estimated. It appeared that the majority of collected specimens were dominated by individuals in size range of 40-64 mm dorso-ventral length (DVL). The maximum size (113 mm DVL & 144.71 g total weight), recorded in S1 (Abu-Qir), was bigger than that recorded elsewhere. The biometric relationships between DVL and hinge length [HL], thickness [THK], anterior-posterior length [APL], nacre width [NW], and nacre length [NL] were studied. All populations showed high to moderate correlations between various combined parameters, with some variability from one station to another. Further correlations were studied between DVL and THK, NL, NW for each size class in all stations. It was concluded that S1 (Abu-Qir) is one of the most suitable sites for specimens collection for seed implantation since oysters attained the highest thickness, flesh weight values, and  largest nacreous layer area. Also, 65-89 mm size range of P. radiata is recommended for seed implantation.