OBJECTIVES: Life-threatening clinical complications can occur in the first years of life in people with homozygous sickle cell disease. There is consensus that a clinical care programme comanaged by a specialist clinic should follow early-life disease identification. In a setting without widespread neonatal screening for this disease, we predict the percentage of affected births that enrol in specialist clinics during childhood, and the percentage that enrol early enough to benefit from penicillin prophylaxis (which is offered until five years of age). SETTING: A retrospective study of enrolment between 1973 and 1999 at three clinics in Jamaica, the country’s only referral centres for sickle cell disease. RESULTS: Among enrolees not screened at birth, observed enrolment by age five was 10.1% (95% confidence interval [CI] 5.7-16.7%) among 1974 births, which is predicted to rise to 35.7% (95% CI 35.0-36.4%) among 1999 births. Observed enrolment by 18 years of age was 45.9% (95% CI 35.7-58.2%) among 1974 births, which is predicted to peak at 61.9% (95% CI 60.5-63.2%) among 1984 births, and fall to 48.9% (95% CI 40.9-56.9%) among 1999 births. Median age at enrolment was 10.5 years (95% CI 10.0-11.3). CONCLUSIONS: Based on 1999 estimates, almost 65% of children affected by homozygous sickle cell disease not identified at birth will not benefit from important early-life clinical intervention, and half will not enrol for specialised care by their 18th birthday. Among patients that enrol, half do so in adolescence when management is less focused on preventive care.