The papers contained in this volume of Acta Horticulturae report the peer reviewed Proceedings of the First All African Horticultural Congress, held in Nairobi between August 31st and September 3rd 2009. The congress was an ultimate culmination of several years of thoughts and discussions by African horticulturalists during several ISHS events. The congress examined ways for horticulture to improve livelihoods in Africa: food security, human health, environmental services, and poverty alleviation through wealth creation. A total of 67 papers are covered in these proceedings out of the 90 oral and 120 posters presented during the congress. The proceedings include papers from plenary or parallel sessions, and of the two side events convened by ICIPE (integrated pest management) and FAO (urban horticulture), but not from the side events on vegetable seed industry in Africa (convened by AVRDC - The World Vegetable Center) or on the promotion of fruit and vegetables for health (convened by FAO). The papers have been re-organized into nine groups: 1. Strategy: Horticulture is a key issue for Africa (J. Ganry, R. Kahane); Lessons from the first all Africa horticulture congress (R. Kahane, W. Kariuki), 2. Agronomy. 3. Crop protection. 4. Economics. 5. Human nutrition. 6. Fruits. 7. Vegetables. 8. Ornamentals. 9. Post-harvest