A survey was conducted in 2014 to determine the prevalence of fungal diseases on sorghum across different agroecological zones in Tanzania and Uganda. In Tanzania, 37 sorghum fields were sampled in Dodoma and Singida Provinces, representing the central drier areas, and in Simiyu, Shinyanga, Mwanza, and Mara Provinces, representing the lake-zone region. In Uganda, 134 fields were sampled across four agroecological zones of Teso, Western, Northern, and West Nile. Farmers were purposively selected, and at least 30 plants per field along two diagonal transects were visually assessed for disease. Ten and 14 diseases were identified in Tanzania and Uganda, respectively. Among the major diseases identified, those more prevalent in Tanzania than in Uganda were leaf blight caused by Setosphaeria turcica (P = 0.0031) and rust caused by Puccinia purpurea (P < 0.0001). Major diseases more prevalent in Uganda than in Tanzania were anthracnose caused by Colletotrichum sublineola (P = 0.0207) and zonate leaf spot caused by Gloeocercospora sorghi (P = 0.0312). We report for the first time the occurrence of ladder leaf spot caused by Cercospora fusimaculans in Uganda and confirm its occurrence in Tanzania. This is the first comprehensive sorghum disease survey report in over 15 years in both countries.