A study was conducted in rural Malawi to verify (a) whether the Partec CyFlow Counter((R)) for CD4+ T-cell lymphocyte counting in HIV-positive individuals could be introduced into a district hospital laboratory and (b) whether it would produce CD4 counts of acceptable quality. CD4+ cell counting was performed using the Partec CyFlow Counter and the results were compared with a reference method (FACsCount). A total of 311 blood samples were analysed and the correlation coefficient for the CyFlow Counter was 0.92 (95% CI 0.89-0.95). Mean CD4 counts using the Partec and the reference methods were 308.2 cells/microl and 316.9 cells/microl, respectively. The mean difference in CD4 count values was -8.68 cells/microl (95% CI -18.8 to 1.4). Mean intra-run variation was -6.84 cells/microl (95% CI -12.9 to 0.79). In the district laboratory setting, the instrument could accommodate up to 75 blood samples per technician per day. After being trained, local laboratory staff found the CyFlow Counter procedures simple to run and the instrument easy to manipulate. The Partec CyFlow Counter produces sufficiently reliable results and the instrument appears robust under field conditions. It could provide a new option for introducing routine CD4+ cell monitoring at the district level in the context of scaling-up antiretroviral therapy in Malawi.