The purpose of this study was to find out the impact of acute respiratory acidosis on serum potassium level during laparoscopy. The study was performed on ninety patients who underwent laparoscopic surgery. Ventilation parameters were kept constant throughout the study. Samples for assessment of blood gases were collected in the following sequence: before pneumoperitoneum, a the 20 th minute of pneumoperitoneum, at the 60th of pneumoperitoneum, and after extubation. The systolic, diastolic pressures and heart rate were recorded simultaneously. Before pneumoperitoneum, heart rate, systolic and diastolic pressures were reduced according to baseline values. With the induction of pneumoperitoneum, both systolic and diastolic pressures returned to the baseline levels except the heart rate. There was a statistically significant increase in potassium level (Control: 3.49 mEq.L-1, determined high level: 3.75 mEq.L-1). Electrolytes, especially potassium, should be monitored during laparoscopy utilizing CO2 pneumoperitoneum and when necessary, ventilatory parameters should be adjusted.