BACKGROUND: Cleft lip and/or palate is the most frequent congenital abnormality occurring in the craniofacial region and is often associated with numerous dental defects such as tooth agenesis, supernumerary teeth, microdontia, taurodontism, crown malformations, or delay in eruption. The prevalence of hypodontia in cleft-affected patients is much higher in comparison with a healthy population. The aim of this study was to evaluate the prevalence of second premolar hypodontia in patients with cleft lip and/or palate. MATERIAL AND METHODS: We performed a retrospective, evaluation of panoramic radiographs and dental casts in the Department of Dentofacial Orthopeadics and Orthodontics, Wroclaw Medical University. Two independent observers evaluated the records of 469 patients with various types of clefts and analyzed dental casts and panoramic radiographs. RESULTS: 202 individuals met inclusion criteria. The sample comprised 120 UCLP patients, 38 BCLP patients, 28 CP patients, and 17 CLA patients. Hypodontia in the premolar region was observed in 39 individuals (19.3%). A total number of 58 second premolars were missing, of which 35 were maxillary second premolars (U5) and 23 were mandibular second premolars (L5). CONCLUSIONS: Estimated hypodontia in the Polish CL/P sample was considerably higher than the hypodontia in permanent dentition reported for a European healthy population. The number of congenitally missing second premolars was higher in the maxillary arch than in the mandibular.