We identified risk factors for postoperative anxiety and quantified their effect on 712 adults between 18 and 60 years of age (ASA I-III physical status) undergoing elective surgery under general anaesthesia, neural blockade or both. The measuring instruments were a structured questionnaire, a pain visual analogue scale, the McGill Pain Questionnaire, the State-Trait Anxiety Inventory, the Montgomery-Asberg Depression Rating Scale, a Self-Reporting Questionnaire-20, and a Self-Perception of Future Questionnaire. Multivariate conditional regression modelling taking into account the hierarchical relationship between risk factors revealed that postoperative anxiety was associated with ASA status III (OR = 1.48), history of smoking (1.62), moderate to intense postoperative pain (OR = 2.62) and high pain rating index (OR = 2.35), minor psychiatric disorders (OR = 1.87), pre-operative state-anxiety (OR = 2.65), and negative future perception (OR = 2.20). Neural block anaesthesia (OR = 0.72), systemic multimodal analgesia (OR = 0.62) and neuroaxial opioids with or without local anaesthesia (OR = 0.63) were found to be protective factors against postoperative anxiety.