OBJECTIVE: To determine the impact of missed visits on CD4 cell count with HIV disease in a Midwest clinic. METHODS: This was a mixed method study consisting of a quantitative retrospective cohort study of missed clinic visits among HIV-infected patients, and a qualitative study to collect information on factors impacting appointment attendance. A drop in CD4 cell count greater than 50 cells/mm(3) from baseline was the primary outcome variable for the quantitative study. The exposure variable was missed visits. RESULTS: Of 77 patients, 16.4% experienced the outcome of interest. Lower visit proportions increased the risk of a CD4 drop (hazard ratio 0.0188, 95% confidence interval 0.001-0.292). For each 10% increase in the missed visit proportion, the risk of a CD4 drop of >50 cells/mm(3) from baseline increased by 33%. Qualitative data suggested that stigma, external support, and physician-patient interactions impacted engagement in care. CONCLUSION: These results may help providers increase patient motivation and ability to attend clinic appointments.