A meta-analysis of 40 studies published between 1981 and 1991, involving 1,053 Ss, was conducted to address the critical issue of whether there was a relationship between psychosocial stress, depression, and some aspects of human immunity. Three meta-analysis procedures were used: (1) Z-score, (2) effect-size, and (3) fail-safe statistics. The study indicated that: (1) there was no significant effect of psychosocial stress and depression on the quantity of B or T cells; (2) there was a significant effect of psychosocial stress and depression on the activity of NK, B, and T cells; (3) there were no significant differences between the effect of psychosocial stress and the effect of depression on the NK, B, and T cells: and (4) the effect of psychosocial stress and depression of NK activity seemed to be stronger than its effect on B or T cells' activity. (Arabic abstract)