The objective of this study was to assess the current prevalence and characteristics of DA of teeth in paediatric patients attending the Clinics of Paediatric Dentistry, Istanbul University. The study consisted a random sample of 1039 patients aged 7-13 years who visited the Department of Paediatric Dentistry of Istanbul University between Sept 2010-Jan 2011. The patients were evaluated clinically and radiographically for the presence of talon cusp (TC), microdontia (MI), macrodontia (MA), tooth agenesis (TA), supernumerary teeth (ST), odontomas (0). The findings were analyzed statistically according to gender, localization, number, morphology by chi-square test. Prevalances of DA were found as: TC 2.02%, MI 0.38%, NIA 0.09%, TA 6.44%, ST 4.33%, 0 0.19%. The gender distribution showed no statistically significant differences (p > 0.05) in prevalances of TC, TA, MI of teeth. ST have been mostly observed in males (p < 0.05). TC was seen mostly as bilateral (p < 0.05). The mandibular second premolar was the most frequently missing tooth (55.2%), followed by the maxillary second premolar (31.3%), and maxillary lateral incisors (28.4%). The majority of ST were mesiodens (64.4%). Data reinforces the importance of early diagnosis of DA in paediatric patients in the treatment planning of paediatric patients.