This work is a multicentre study investigating HIV subtype distribution, time-trends in the HIV-1 subtype variability.

Novel unique AB recombinant forms (URFs), previously not reported in Poland were identified.

Observed AB URFs likely result from sexual mixing and reflect shift from injection drug use to sexually driven epidemics.

Infections with non-B clades were more associated with heterosexual transmissions and associated with delayed HIV diagnosis.

Differences in the subtype distribution across regions of Poland are significant and may guide epidemiologic interventions.