In this paper, the causes of early embryo abortion in the reciprocal crosses between Phaseolus vulgaris L. (a cultivar) and Phaseolus coccineus L. (a wild form) were studied. Methacrylate resin sections, 3–5 μm thick, of 3 to 14 day-old seeds were used to examine the embryo developmental stages and the state of seed tissue. It was observed that, embryos aborted at different developmental stages (globular to early cotyledon) depending on the maternal parent. The use of P. coccineus cytoplasm resulted in a higher number of abortion than in reciprocal crosses. Many of them took place between 5 and 6 days after pollination (DAP). Histological analyses permitted to observe that the embryo development was slower in the cross between P. coccineus and P. vulgaris, compared to parental seeds. It would be related to a deficient endosperm development in reciprocal crosses and, in some extent, hypertrophy of the suspensor might be the main cause of early embryo abortion. Then, it would be practical to overcome this incompatibility by rescuing the embryo at the globular stage of development.