We analyzed 100 control individuals and 60 patients with psoriasis vulgaris from the population of Campinas, Brazil. Typification of class II HLA alleles (HLA-DRB1-5 and -DQB1) was carried out through the DNA/PCR/SSP at medium and high resolution. DNA was extracted through a salting-out procedure: 13 DRB1 alleles, 3 DRB3 alleles, 1 DRB4 allele, 2 DRB5 alleles, and 5 DQB1 alleles were identified at a medium resolution using the PCR/SSP, and 45 DRB1 alleles were identified at a high resolution in analyzed patients. Results showed associations with psoriasis vulgaris: positive associations HLA-DRB3*02 (p < 0.05, chi(2) = 5.10, RR = 2.14); HLA-DRB1*0102 alleles (p < 0.05, RR = 5.44). Negative associations were found for HLA-DRB4*01 (chi(2) = 3.23, RR = 0.55) and HLA-DRB1*1302 alleles (p < 0.05, RR = 0.23). The haplotypes revealed positive association for HLA-DRB1*0102/DQB1*05 (p < 0.05, RR = 5.44) and HLA-DRB1*0701/DQB1*03 alleles (p < 0.02, RR = 9.00). These findings suggest a possible association of the DRB1 allele with the group of patients showing an early onset of the illness, as well as an association with haplotypes HLA-DRB1*0102/DQB1*05 and HLA-DRB1*0701/DQB1*03.