For adults with sickle cell disease (SCD), cardiac changes are well described and may account for up to one-fourth of disease-related mortality. Much less is known about heart disease in pediatric SCD patients. This retrospective study analyzed a contemporary cohort of children with SCD followed at a single tertiary care center. The study aimed to evaluate the effect of SCD on left main coronary artery (LMCA) dimensions in the contemporary pediatric population. The echocardiography database was searched for studies of children with SCD from 2000 to 2009. The LMCA diameter was remeasured offline from digital images. Digital echocardiographic studies of 68 children (35 boys) 11.7 ± 4.6 years of age with SCD were analyzed. All the patients had normal systolic function as measured by fractional shortening. The left ventricular end-diastolic dimension (LVEDD) for 34 % of the pediatric SCD patients showed a dilated LV. In 24 % of the children, a LV mass index (LVMI) greater than 50 g/m^2.7 denoted LV hypertrophy. Application of sex-specific normal values showed that 60 % of the boys and 33 % of the girls had an increased LVMI. The LMCA diameter was enlarged in 43 % of the SCD children, including 26 % with an LMCA z-score higher than 3. This study found a higher incidence of LMCA dilation in a pediatric referral population with SCD. The findings also validated an increased LVMI in the contemporary SCD patient population, which was noted previously. This study adds the need to include assessment of coronary arteries in cardiac evaluation of SCD patients, and special attention should be paid to patients with a high-normal to high coronary z-score.