Retained teeth are teeth that have formed inside the bone, but have not erupted. Those teeth are a noted problem in orthodontics because of the long duration of required treatment. Aims: The main objective of the thesis is to predict the frequency of upper canine retention and to estimate the frequency of the bilateral retention appearance in croatian population. Materials and methods: From the dental data-base, 386 orthopantomograph scans have been analysed and 5 CT scans. The patients were both male and female (older then 14 years, with an average age of 152). The patients were registered and treated in private orthodontic offices in Split and Zagreb. The research took place during April and May, 2016. The radiographs were selected randomly, and used to examine the percentage of the retained upper canines. Results: The results have shown a low percentage of upper canine retention (4,40%). From the total number of 17 patients with retained upper canines, bilateral retention has been recorded among 5, leading to a percentage of 29,41%. Beside OPG-s, CT scans were also required in 1,29% of cases. The divergence in frequency of the upper canine retention among the patients treated in Zagreb and Split, showed a minor deviation: 0,81%. Conclusion: The research has confirmed the hypothesis that the retention of the upper canine is a rare anomaly that appears in less than 5% of the patients. The research has also shown that there are fewer cases of bilateral retention compared to unilateral.