Background: There is a paucity of epidemiological data on biopsy-proven glomerulonephritis (GN) in Poland. The aim of this study was to assess the epidemiology of renal diseases based on histological diagnosis in the region of Central Poland over the last two decades. Methods: Retrospective analysis of the results of 746 consecutive native kidney biopsies performed in the Caucasian adults from 1990 to 2010 in a single tertiary nephrology center serving an area of Central Poland. Results: Primary GN was found in 81.4% of all biopsies. The mesangioproliferative GN including IgA nephropathy was the most frequent type of primary GN (51.2%). Membranoproliferative GN was diagnosed between 1990 and 2000 more frequently than in the following decade (26.7 vs. 7.3%, p < 0.001). There was a significant increase in the incidence of FSGS (4.8 vs. 17.3%, p < 0.001) and MCD (5.1 vs. 11.2%, p < 0.001) over time. Secondary GN was documented in 18.6% of biopsies and lupus nephritis was the most frequent cause (34.5%). Conclusion: Our analysis showed the decrease in the incidence of membranoproliferative GN with the parallel increase of FSGS and MCD over the last twenty years. Mesangioproliferative GN including IgA nephropathy remains the most frequent type of GN observed in our region.