Background: Smoking prevalence is very high among people living with HIV/AIDS, and smoking is riskier for them than for HIV-seronegative people. Promoting smoking cessation among HIV-infected people is therefore an emerging public health priority. Raising cigarette prices is usually considered as one of the most effective ways to reduce smoking, but its effectiveness has never been studied among HIV-infected smokers. Methods: We studied the impact of cigarette price increases among HIV-infected smokers, with data extracted from the French cohort study APROCO-COPILOTE conducted between 1997 and 2007 among 1,146 patients. Data regarding respondents smoking status was collected every 8 months over the first 5 years, and every 12 months thereafter. Results: We found striking differences across transmission groups regarding socio-demographic background and smoking prevalence. The Intravenous Drug Use (IDU) group was characterised by a lower socioeconomic status, a higher smoking prevalence and a smaller decrease in this prevalence over the period 1997-2007. The homosexual group had a higher socioeconomic status, an intermediate smoking prevalence in 1997, and the highest rate of smoking decrease. In the dynamic multivariate analysis, smoking remained correlated with indicators of socioeconomic disadvantage and with infection through IDU. Aging and cigarette price increase had a negative impact on smoking among the homosexual group, but not for the IDU group. Conclusion: Among seropositive people, just as for the general population, poor smokers are poor quitters. Public health authorities should consider interventions which are not smoking-specific, but which contribute to improve the living conditions of the most deprived HIV-infected smokers.