Objective: The aim of this study is to evaluate relationship between ostiomeatal complex variations (OMC) and maxillary sinus pathologies in children and adolescents using cone-beam computed tomography (CBCT). -/- Methods: CBCT images of 72 patients (44 males and 28 females) aged 7-18 years were evaluated retrospectively. Presence of nasal septal deviation (NSD), nasal septal pneumatization (NSP), concha bullosa (CB), accessory maxillary ostium (AMO), agger nasi cell (ANC), Haller cell (HC), Onodi cell (OC), ethmoid sinusitis and maxillary sinus pathologies were investigated. (...) Maxillary sinus pathologies were classified. Correlations of OMC variations with each other, maxillary sinus pathologies and ethmoid sinusitis were investigated. Chi-square test was used to analyze relationships among variables and distribution of parameters. -/- Results: NSD was determined in 70.8%, NSP in 40.3%, ethmoid sinusitis in 75%, maxillary sinus pathology in 34.8% of images. OMC variations rates were detected as CB 31.3%, AMO 16%, ANC 16%, HC 24.3% and OC 18.8%. The most common maxillary sinus pathology was localized mucosal thickening, with a rate of 15.3% on right and 22.2% on left. Statistically significant differences were determined between almost all OMC variations with each other, and between anatomical variations in OMC with maxillary sinus pathologies except for NSP and AMO (p < 0.05). The presence of ethmoid sinusitis was more common in males (p =0.026). -/- Conclusion: Anatomical variations in OMC had no significant effect on maxillary sinus pathology except for NSP and AMO. Besides, most of anatomical variations in OMC were statistically significantly correlated with each other. CBCT visualization of these variations is important for sinonasal surgery and is an effective method in children and adolescents with low radiation dose and high image quality compared to computed tomography. (shrink)