Background: Pulmonary hypertension (PH) is a long-term complication of sickle cell anaemia (SCA). The most obvious pathophysiologic consequence of PH is on the right heart, causing right ventricular and right atrial dilatation with subsequent right heart failure. Progressive dilatation of the right atrium and right ventricle, makes echocardiographic evaluation of right heart linear dimensions important in the evaluation of patients with PH. Aim: To assess possible relationship between mean pulmonary artery pressure and right heart linear dimensions. Methods: This was a cross-sectional study involving children with SCA aged 6 months -15 years. The study was conducted from September 1^st 2013 to 30^th August 2015, at the SCA clinic of the Department of Paediatrics, Usmanu Danfodiyo University Teaching Hospital, Sokoto. North-Western Nigeria. Result: Three hundred children with SCA in steady state were enrolled in to the study. The age range of the children was 6 months – 15 years, with mean age of 6.5 ± 4.1 years. Subjects were grouped in to three, group one comprises of children with normal pulmonary artery pressure (PAP) defined as peak tricuspid regurgitant velocity (TRV) of ≤ 2.5m/s and mean pulmonary pressure (MPAP) of < 25 mmHg; group two comprises of children with elevated PAP, defined as TRV ≥ 2.5 m/s and MPAP of < 25 mmHg; and group 3 comprises of children with PH, defined as mean pulmonary artery pressure (MPAP) ≥25 mmHg. The mean values in millimetre of the right atrial (RA) major axis (34.5 ± 5.6 vs 31.2 ± 8.6, p <0.001), RA minor axis (30.2 ± 6.1 vs 25.8 ± 6.7, p < 0.001), right ventricular (RV) basal diameter (33.0 ± 15.8 vs 26.0 ± 9.4, p = 0.01), RV mid-cavity diameter (35.9 ± 6.9 vs 21.8 ± 8.9, p < 0.001) and RV longitudinal diameter (56.7 ± 11.4 vs 45.2 ± 16.1, p < 0.001) were significantly higher in patients with elevated PAP compared to those with normal PAP. RA minor axis, RA major axis, RV mid-cavity diameter and RV longitudinal diameter independently varies with mean pulmonary artery pressure (MPAP), with 86% (44% of 51%) of the variability accounted for by the RA minor axis alone. Conclusion: Right heart linear dimensions have significant association with MPAP, and can be of use in the echocardiographic evaluation of PH among children with SCA.