Background: Sickle cell diseases (SCDs) are chronic destructive processes on vascular endothelium initiating at birth all over the body. We tried to understand whether or not there is an association between chronic obstructive pulmonary disease (COPD) and severity of the SCDs.Methods: All patients with the SCDs were taken into the study.Results: The study included 411 patients with the SCDs (199 females and 212 males). There were 60 patients (14.5%) with the COPD. Mean age of the patients was significantly higher in the COPD group (33.0 versus 29.5 years, P=0.005). The male ratio was significantly higher in the COPD group, too (80.0% versus 46.7%, P<0.001). Smoking was also higher in the COPD group, significantly (36.6% versus 9.9%, P<0.001). Parallel to the smoking, alcoholism was also higher among the COPD cases, significantly (3.3% versus 0.8%, P<0.05). Beside these, transfused red blood cell units in their lives (69.1 versus 32.9, P=0.001), priapism (10.0% versus 1.9%, P<0.001), leg ulcers (26.6% versus 11.6%, P<0.001), digital clubbing (25.0% versus 7.1%, P<0.001), coronary heart disease (26.6% versus 13.1%, P<0.01), chronic renal disease (16.6% versus 7.1%, P<0.01), and stroke (20.0% versus 7.9%, P<0.001) were all higher among the COPD cases, significantly.Conclusion: SCDs are chronic catastrophic processes on vascular endothelium particularly at the capillary level, and terminate with accelerated atherosclerosis induced end-organ failures in early years of life. COPD may be one of the terminal endpoints of the diseases.