Characteristics of N mineralization and nitrification in six pairs of garden soils and paddy soils gathered from the suburbs of Nanjing, were investigated in a 28-day incubation experiment. The garden soils were formerly paddy soils about 20 years ago. Results show that after 28 days' incubation, in four of the six pairs, garden soils were lower than the paddy soils in N mineralization, both quantity and rate, and the other two showed little difference. Following urea application, in 5 of the 6 pairs, garden soils were lower than paddy soils in N nitrification rate. Moreover, soil N mineralization and nitrification rates were significantly related to soil pH and soil available P content.