Over a 10-year period, 28 Arab children with autosomal recessive osteopetrosis were seen in two hospitals in Riyadh, Saudi Arabia. Eighteen (64%) had osteopetrosis associated with metabolic acidosis probably due to a renal tubular defect; nine (32%) had a malignant infantile form of osteopetrosis and one had a mild form with delayed onset. Parental consanguinity was 56% and 40% among patients with and without acidosis respectively. Somatic and psychomotor retardation and recurrent bone fractures were common in both groups. Dental caries, cerebral calcification and optic atrophy were more frequent in patients with acidosis, while anaemia, hepatosplenomegaly and deafness were more common in patients without acidosis. To guarantee optimal rehabilitation, children with this progressive disease require an early multiteam approach.