A study was undertaken to identify and characterize the viruses causing nephritis in poultry with special reference to infectious bronchitis virus (IBV). Out of 14 broiler chicken kidney samples and 8 layer chicken kidney samples yielding a titre of 1:16 and above in IBV-specific haemagglutination (HA) test, 11 samples in broiler chicken and two samples in layer chicken were positive for IBV isolation in ECE of SPF origin. IBV-specific HA test can be a viable screening method for nephropathogenic IBV in broiler type of chickens. Reverse Transcriptase Polymerase Chain Reaction for partial M and N genes was carried out to amplify 1020 bp and RT-PCR for entire S1 gene to amplify 1700 bp. Direct sequencing of partial M and N genes of the isolates Ind/KA/07/1 and Ind/TN/07/2 was carried out. Multiple sequence alignment for membrane glycoprotein and 5b protein of N gene with reference strain M41 revealed many point mutations, short deletions and insertions. Phylogenetic analysis of the amplified part of the two isolates indicated that these were Mass variants. The isolate Ind/KA/07/1 showed more variation in these alignments and restriction site mapping than isolate Ind/TN/07/2.