Introduction & Objective: The aim of this study was detection of incidence of arrhythmia and hypotension during mediastinal manipulation due to transhiatal esophagectomy and evaluation of related factors. Materials & Methods: In this prospective study we selected 61 patients undergone transhiatal esophagectomy during 2years (2006-2007) in the Al-Zahra hospital. The demographic information, site of tumor, cardiopulmonary function, nutrition, per operation and post operation complications (i.e. arrhythmia and hypotension), histopathology, duration of surgery, duration of mediastinal manipulation, amount of hemorrhage, need of reoperation, need to transfusion, and death rate were evaluated by chi-square, exact fisher, logistic regression, and T tests methods. Results: 8.2% of patients before, 50. 8% during, and 11.2% after mediastinal manipulation showed arrhythmia. Need to transfusion, pathology of tumor, pre-existing arrhythmia, amount of hydration, and FEV1< 2 liter were significantly correlated with arrhythmia. 8.2% of patients before and 55.7% during mediastinal manipulation showed hypotension. Duration of manipulation, amount of hemorrhage, systolic and diastolic pressure before manipulation, and FEV1< liter were significantly increased risk of hypotension during operation. Conclusions: Our data showed the amount of hydration, transfusion, premanipulation arrhythmia, and pulmonary function should be controlled to decrease the risk of arrhythmias. Minor mediastinal manipulation, less intraoperative hemorrhage, improvement of pulmonary function, and careful blood pressure monitoring can reduce the risk of hypotension.