A study is going on in the Southern part of Cameroon, where about 50;of Cameroons rubber is planted, to evaluate the resistance of new genetic material, including some traditional clones, to two major leaf diseases (Colletotrichum gloeosporioides and Corynespora cassiicola). This area is characterised by a bimodal rainfall pattern. Results over five years indicate significant differences in the susceptibility of the testes clones to both diseases. For most of the clones, there was no significant differences in the susceptibility of the two diseases. However, the severity of Corynespora was generally higher than that of Colletotrichum. There was also a significant variation in disease severity from one year to another for most of the clones, with a tendency to increase over the years. The general incidence of leaf disease diseases was highest in RRIC 110, PR 228, GU 1276, RRIM 706, GU 198 and MDX 98 while MDF 72, RO 58, MDF 362, MDX 17, RO 46 and RO 42 showed the most resistance. Meanwhile, GU 4673 showed high susceptibility to Colletotrichum, but was appreciably tolerant to Corynespora. This study suggests that, clones such as MDF 72, RO 58, MDF 362, MDX 17, RO 46 and RO 42, by virtue of their resistance to leaf diseases, may constitute a good genetic base for development of new clones. Meanwhile, RRIC 110, PR 228 and GU 1276, by virtue of their susceptibility, especially to Corynespora may have to be avoided in a breeding programme.