The existence of nutritional deficiency rickets among infants in sunny Riyadh was confirmed radiologically. Most of the rachitic infants were breast-fed, some received unsupplemented infant feeding formulae, and all live in an environment that is devoid of sunlight. Their mean age at the time of onset was 10.5 months. 25-Hydroxyvitamin D (25OHD) levels were found to be low in mothers of the rachitic infants. This maternal deficiency as a factor in pathogenesis of rickets in the infant is discussed. Proposals are made to prevent the occurrence of rickets on this scale.