Tomato (Solanum lycopersicum Mill.) is most popular vegetable crop grown in the world, next to potato. Tomato crop infected by many diseases among those important foliar fungal diseases are septoria leaf spot, early blight, late blight and powdery mildew. Now a day’s biological control is becoming more important and Bacillus subtilis is very effective against foliar diseases. A roving survey was conducted during Kharif 2014 to know the prevalence of Bacillus subtilis in rhizosphere and severity of tomato diseases in Haveri, Dharwad and Belgaum districts of northern Karnataka and soil samples were collected during the survey for isolation of B. subtilis. The bacterial antagonist B. subtilis was more prevalent in Dharwad and Haveri districts. Among three districts, Haveri recorded the maximum severity of alternaria leaf spot (27.71%). Severity of septoria leaf spot was maximum (16.80%) in Belgaum district whereas, severity of powdery mildew was maximum (9.66%) in Dharwad district. Wherever the B. subtilis was present the severity of diseases was low. Although there was no much difference in mean disease severity, there was clear cut variation with respect to disease severity at different locations which may be due to variability in seasonal and weather conditions prevailing in these districts