Clinical application of genetic clonality analysis by PCR has been available in feline lymphoma. However, it is in under dispute whether the analysis can be applied for cellular lineage determination. To evaluate utility of the analysis for lineage determination, the results between immunohistochemistry and the genetic analysis were compared. Based on the result with immunohistochemistry, sensitivity of the primer for IgH was 89% and specificity was 75%. Sensitivity of the primer for TCRγ was 25% and specificity was 100%. Cross-lineage IgH rearrangement was found in 25% of T-cell lymphomas. The present study suggests that the genetic analysis had better be applied as not a definite but an adjunctive tool for lineage determination in feline lymphomas.