Background: Sternal incision pain is the most common patient complaint after open heart surgery. It can impede normal respiration, deep breathing, effective coughing, and sputum clearance, and may result in respiratory dysfunction Aim: This study aimed to evaluate effect of cold gel pack intervention on controlling pain associated with incentive spirometry post open heart surgery. Design: A Quasi experimental design was utilized. Setting: The study was conducted in cardiothoracic intensive care unit and cardiothoracic department of Benha University Hospital. Sample: A Purposive sample of 60 adult patients were included in the study. Tools of data collection: Three tools were used for data collection; Tool I Structured interview questionnaire, Tool II Subjective pain assessment sheet, Tool III Objective pain assessment sheet. Results: 36.7% of control group had severe pain and 33.3% of intervention group had a moderate  pain during first day post intervention , while during the second day 63.3% had moderate pain and 53.3% had mild pain, respectively to be post one week  moderate level among 50.0% of control group and mild level among 73.3% of intervention group, with a significant overall change in pain score within the control group ( p=0.040*) and highly significant ( p=<0.001**) within the intervention group throughout post intervention phases. Conclusions: Application of cold gel pack intervention was effective for reducing incisional pain and improving physiological parameters associated with incentive spirometry in patients post coronary artery bypass graft. Recommendations: Cold gel pack application should be applied as a non-pharmacological treatment option before incentive spirometry for post-operative CABG patients.