In order to understand the genetic diversity of virus isolates associated with the human immunodeficiency virus type one (HIV-1) epidemic in Northern Greece, 51 specimens from HIV-1 infected individuals were classified into subtypes by sequence-based phylogenetic analysis of the polymerase (pol) region of the viral genome. Forty two (82.3%) specimens were identified as pol subtype B, three (5.9%) as A, and one (2%) as CRF01_AE, while the remaining five (9.8%) specimens appeared to be complex recombinants, belonging to the Cypriot/Greek form CRF04_cpx. The proportion of CRF04_cpx strains is larger than previously reported, suggesting that the CRF04_cpx is significantly contributing to the Greek HIV-1 epidemic.