Urinalysis by the IITP method in 115 patients with lymphatic tumors has shown that in half of them, BJ protein can be identified. The authors' and reported data evidence the lack of BJ proteinuria in normal people and in patients afflicted with other diseases. Since BJ proteinuria was demonstrable with the minimal tumorous mass in successfully treated patients with CLL and LC, the IITP method was used for excluding a morphologically undemonstrable lymphatic tumor in 23 patients with rheumatic diseases, AIHA, and splenomegaly of obscure genesis. Based on the identified BJ protein secretion in the urine, the diagnoses of CLL (I), LC (2), and LS (I) were proved in 4 cases. Later on these diagnoses were supported by the cytologic and histologic findings.