To assess the occurrence of hypodontia (except 3rd molars) in a population of orthodontic patients.A retrospective case study.Private orthodontic practice in NairobiSix hundred and fifteen orthodontic patients aged eight to fifteen years.Hypodontia occurred in 39 children (6.3%). The missing teeth were observed in 24 males (7.2%) and 15 females (5.3%). Of the children with hypodontia, about 80% lacked one or two teeth, 54% had hypodontia involving anterior teeth, 18% lacked single posterior teeth and 8% had two or more teeth missing in the same quadrant. The highest recorded number of missing teeth in any one individual was seven. The most frequently missing teeth were mandibular 2nd premolars (30%), maxillary 2nd premolars (24%) and maxillary lateral incisors (22%) in that order.Our data for hypodontia were within the wide range reported in the literature. The finding of patients with hypodontia involving the anterior teeth and others missing more than two teeth in the same quadrant was an indication of a great need for orthodontic treatment. The present findings reiterate the neeed for a thorough radiographic evaluation of patients prior to removal of permanent teeth for orthodontic reasons.