Patients after cardiac surgery experience significant pain, but cannot communicate effectively due to opioid analgesia and sedation. Identification of pain with validated behavioral observation tool in patients with limited abilities to self-report pain improves quality of care and prevents suffering. Aim of this study was to validate Polish version of behavioral pain scale (BPS) in intubated, mechanically ventilated patients sedated with dexmedetomidine and morphine after cardiac surgery.Prospective observational cohort study included postoperative cardiac surgery patients, both sedated with dexmedetomidine and unsedated, observed at rest, during a nociceptive procedure (position change) and 10 minutes after intervention. Pain control was achieved using morphine infusion and nonopioid coanalgesia. Pain intensity evaluation included self-report by patient using numeric rating scale (NRS) and BPS assessments carried out by 2 blinded observers.A total of 708 assessments were performed in 59 patients (mean age 68 years), predominantly men (44/59, 75%). Results showed very good interrater correlation between raters (interrater correlation scores >0.87). Self-report NRS scores were obtained from all patients. Correlation between NRS and BPS was relatively strong during nociceptive procedures in all patients for rater A and rater B (Spearman R > 0.65, P < .001). Both mean NRS and BPS scores were significantly higher during nociceptive procedures as compared to assessments at rest, in both sedated and unsedated patients (P < .001).The results of this observational study show that the Polish translation of BPS can be regarded as a useful and validated tool for pain assessment in adult intubated patients. This instrument can be used in both unsedated and sedated cardiac surgery patients with limited communication abilities.