OBJECTIVES: Therapies for HIV and cancer draw attention due to both high unmet need and high costs.  In some cases, HIV treatments are approaching the prices of cancer treatments.  However these disease states are often reviewed differently by payers and HTA agencies.  NICE, for example, does not perform HTAs for HIV therapies while other European countries do. We examined the relative differences in prices between HIV and cancer therapies across several European countries to identify the potential impact of HTA reviews METHODS: We included therapies approved for use 2004-2010 in HIV (Atripla, Trizivir, Reyataz, Norvir, Truvada, Invirase, Celsentri, Isentress, Fuzeon) and cancer (Alimta, Avastin, Erbitux, Sutent, Tyverb,Taxotere, Nexavar). Current yearly treatment prices  (2010) were identified for all therapies for UK, FR, DE, IT, and ES.  Price differentials between the UK and other countries were determined for each treatment.   Mean country price differentials (UK reference) were compared. RESULTS: HIV therapies were on average 30% (median differential 29%) lower in price in the UK than other countries.  Price differentials for HIV therapy ranged from -18% (higher price in UK) to 75% (less expensive in UK).   Cancer therapy prices averaged 36% (median 36%) lower in UK than other countries.  Price differentials for HIV therapy ranged from 6% to 80% (lower price in UK) with a median of 36%.  The apparent discrepancy between mean country differentials was not present if the single HIV therapy was more expensive in the UK than other European countries (Norvir was excluded). CONCLUSIONS: Across 9 HIV therapies and 7 cancer treatments, all treatments were on average lower in price in the UK.  However, the price differential was not substantially different across the 2 therapy areas.  There is little evidence supporting an upward price pressure due to a lack of economic-driven HTA reviews of HIV products when compared to oncology therapies.