The xenial and metaxenial effects of five different male sources on cross pollination of three pistachio cultivars, were studied in 1990 and 1991 in Rafsanjan/Iran. The pollen grains used were P. atlantica Desf., P. mutica F.& M., P. vera L. (Momtaz), P. vera L. (Soltani), and an open pollination. The female cultivars chosen were `Owhadi', `Kalleh-ghuchi', and `Momtaz', which occupy the largest cultivation area. Experiment was done in two successive years in a completely randomized design. Results of this study agreed with previous studies regarding the retardance of pistachio nut development by wild pollen species rather than P. vera L. The greatest change in various characteristics of nuts, e.g., kernel weight and shell splitting, occurred when P. mutica F.& M. pollen grains used followed by P. atlantica Desf. pollen grains. Thus, some manifestations of xenia and metaxenia could be inferred. In general, larger kernels and increased shell dehiscence resulted from the use of P. vera L. pollen grains. Greater kernel weight of `Kalleh-ghuchi', higher shell splitting of `Momtaz', and higher blank of `Owhadi' produced by pollination with P. vera L. in some extent could also be cultivar characteristics.