Over 60% of cassava the production occurs in western Kenya. Farmers grow a wide range of traditional varieties while introductions from IITA are also grown. The popular varieties are: Tereka, Adhiambo lera, Tamisi, Serere and Kibandameno.  Constraints to cassava production are biotic, abiotic and socio economic. In 1995, a virulent form of African cassava mosaic disease, termed Ugv, devastated all the cassava crops in Western Kenya. We have introduced a large number of cassava clones first screened at Serere, Uganda. The germplasm is evaluated for resistance to CMD, cassava bacterial blight, anthracnose and cassava green mite. The clones are also evaluated for cyanide potential, yield, adaptability and acceptability. Released clones are rapidly multiplied under a three-tier system (primary, secondary and tertiary). Two varieties, SS4 and Migyera, were released in 1998 and primary sites have bulked and distributed over 24 million mini-stems in the region. Extension agencies and farmers have been trained in rapid multiplication techniques, processing and utilization.  Challenges facing cassava production include: development of early-bulking maturing varieties, more rapid multiplication, development of varieties with longer post-harvest storage capacity, and development of varities with better local adaptation.