© The Author 2014. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. Objective. The aim of this study was to determine whether the proportions of naive and memory CD4+ T cell are independently associated with the metabolic syndrome (MetS) in patients with SLE. Methods. This cross-sectional study was conducted in SLE patients seen at our rheumatology department between September 2013 and April 2014. CD4+ T cell subpopulations were examined by flow cytometry. The association of MetS and CD4+ T cell subpopulations was examined by Mann-Whitney U-test and by multivariable analysis, adjusting for all possible confounding variables. Results. One hundred and seventeen patients were evaluated. Their mean age was 44.6 years (s.d. 12.6), 109 (93.2%) were female and all patients were Mestizo (mixed Caucasian and Amerindian ancestry). Fifty-two patients (44.4%) presented with MetS. Disease duration was 7.6 years (s.d. 6.8). The percentage of naive CD4+ T cells was 25.0 (s.d. 12.7) and memory CD4+ T cells was 66.7 (s.d. 13.2) and the memory:naive CD4+ T cell ratio was 4.3 (s.d. 5.6). In multivariable analysis, the percentage of naive CD4+ T cells was negatively associated with the presence of MetS [odds ratio (OR) 0.959 (95% CI 0.923, 0.997), P = 0.033], whereas the percentage of memory CD4+T cells and the memory:naive CD4+ T cell ratio were positively associated with its presence [OR 1.040 (95% CI 1.003, 1.078), P = 0.031 and OR 1.238 (95% CI 1.041, 1.472), P = 0.016, respectively]. Conclusion. In the SLE patients studied, a lower percentage of naive CD4+ T cells, a higher percentage of memory CD4+ T cells and the memory:naive CD4+ T cell ratio were independently associated with the presence of MetS. This association could reflect the impact of immunosenescence among SLE patients with cardiovascular morbidity.