In November 1999 we started the quality control exercise for Polish institutions involved in HLA typing. Five out of eleven invited institutions responded favourably and took part in the first run of the workshop. In the second trial, presently reported, number of labs increased to eight. Each centre received 4 blood samples for serological typing of HLA class I and 5 samples for DNA HLA class II typing. As in the previous workshop, HLA class II typing should be performed at least for DRB1 alleles at the low resolution level. The paper presents the results of the second run of standardisation.