A massive soil-testing programme was undertaken under the Karnataka Community Based Tank Management Project to create awareness about soil health among the farmers. Soil samples from command areas of 910 tanks from four agro-climatic zones covering 46 talukas belonging to ten project districts of north Karnataka were analyzed for pH, organic carbon, available P2O5 and K2O and DTPA extractable Zn and Fe. The results indicated that soils of transition zone (Zone 1 & 8) were neutral (7.22 and 6.93, respectively), and that of northern dry zone (Zone 3) were alkaline (7.94) and that of hilly zone (Zone 9) were acidic (6.39) in pH. Low organic carbon soils comprised 57 per cent in Zone 2 & 3, whereas soils with medium organic carbon were predominant in Zone 1, 8 and 9. Sixty five percent of soil samples recorded medium available P2O5 in Zone 8 compared to predominance of low P2O5 in other zones representing both dry and heavy rainfall areas. Similarly, Zone 8 soils were predominantly high and soils of other zones were medium in available K2O. DTPA extractable zinc was predominantly deficient in soils of Zone 1; about half of the samples were deficient in Zone 2 & 3 and zone 8, and predominantly sufficient in Zone 9. With respect to iron, 50 per cent of Zone 1 soils were deficient whereas soils of other zones were nearly sufficient. Soil fertility maps were prepared using taluka as a unit based on predominant class for that taluka. The variability of Zone 2 & 3 soils with respect to organic carbon and available P2O5 and K2O was high and the lowest variability for these parameters was observed in Zone 8.