The pejibaye appears to have two strategies to insure cross-pollination. One of these appears to be a quantitative genetic factor inhibiting self -pollination. To study this factor two series of controlled self-pollinations were made in two different juvenile populations. The first population presented an average of 19,121 self-compatibility, measured as percentage of fertil fruit produced from all. flowers. However the coefficient of variation was extremely high. Open-pollination on the same trees produced only 22% fertil fruit, with a lower coefficient, of variation, suggesting that fruit, set was generally pooh. in this population at that time. The second population presented an average of 37.621 self-compatibility, with a lower coefficient of variation. Variation within trees was also detected and shown to be considerable. Overall, self-compatibility varied from 0 to 81%, with an non-normal distribution. The use of juvenile plants may be the reason for high variability within trees. Although little self-incompatibility was found in these populations, this characteristic is recomended as a descriptor for germplasm banks and should be obtained on adult plants to avoid high juvenile variability.