This study has provided a comprehensive list of viruses affecting cowpea in Uganda for the first time, most common viral combinations in the field, and effects of individual and multi-virus infection on symptom severity, growth and grain yield. The study showed the most widely distributed and economically important cowpea viruses as CMV, CPMMV, CPSMV, CYMV CPMoV and CABMV. These viruses occur either singly or in mixtures. The study also noted that Teso sub region has higher incidence of viruses compared to other regions. The study showed that mixed virus infections are associated with higher disease severity and yield losses than single virus infections. Control of these cowpea viruses should focus on breeding for resistance to virus combinations since most of the viruses occurred naturally in singles and mixtures. This book will help plant breeders and plant virologists and other scientists intending to work on cowpea Viruses in the world