Many complications of sickle cell trait have been well-established, but associations with additional disease states remain controversial. We conducted a retrospective cohort study to examine the frequency of receiving a diagnosis of thromboembolism, pulmonary embolism (PE), ischemic stroke, renal disease (acute, chronic), coronary artery disease (CAD) and congestive heart failure (CHF) in patients with sickle cell trait. A total of 13,964 adult African Americans registered in the Kaiser Permanente Northern California (KPNC) health system (Oakland, CA, USA), were included based on laboratory and diagnostic code data for the years 1995-2008: 2642 with sickle cell trait, 11,183 with normal hemoglobin (Hb) and 139 with sickle cell disease. Disease outcomes were obtained from coded diagnoses. The adjusted relative risk of PE and chronic kidney disease in sickle cell trait patients compared to patients with normal Hb were 1.37 [95% confidence interval (CI) 1.07-1.75] and 1.13 (95% CI 1.03-1.23), respectively. There were no other significant differences in the outcomes for sickle cell trait patients compared to patients with normal Hb.