Pain prevalence among inpatients is an important indicator of quality care; it may reach over 80% in various clinical settings. A cross-sectional survey was conducted in a teaching hospital to depict benchmark data regarding pain prevalence and predictors among the entire inpatient population. Overall 892 patients, ≥6 years old and hospitalized for at least 24 h in 57 hospital wards were interviewed using an internationally applied questionnaire. Patients self-reported their pain intensity at the time of the interview (T0) and worst pain perceived during the previous 24 h (T-1), using a numerical rating scale (NRS) and indicated current pain duration. Specific pain predictor data (hospital stay, gender, age and marital status) were obtained from patient medical charts. Pain prevalence at T0 was 38% and 52% at T-1. Pain was moderate to severe (NRS ≥ 4) in 25% of the patients at T0 and in 40% at T-1. High pain prevalence was found (at T0 and T-1, respectively) in Radiotherapy (63%;77%), Obstetrics (68%;54%), and Surgery (59%;45%) wards. Gender was a prominent determinant as pain was significantly associated with females. Pain prevalence was high among young adults or divorced/separated individuals and low among pediatric patients (20%). Protracted hospitalization and prolonged pain duration were associated with major pain severity. Results yield Quality Assurance interventions to ameliorate pain undertreatment. Predictor analysis suggests that attention should be paid to pain management in young adults, socially vulnerable patients and those with protracted hospitalization and pain.