Background Existing evidence suggests that administration of intravenous fluids has been shown to improve outcomes including pain in gynecological laparoscopic surgery but the optimum fluid dose has not been determined. Aims To determine the effect of administration of intravenous fluids on post-operative pain and pulmonary function after gynecological laparoscopy. Methods In a prospective randomized double-blinded study 100 ASA 1 and 2 elective patients undergoing gynecological laparoscopy were randomized to receive intravenous compound sodium lactate 10 ml kg −1 (CSL10-restrictive) or 30 ml kg −1 (CSL30-liberal) administered intra-operatively. The primary outcome measure was the post-operative pain score at 24, 48 and 72 h, assessed by 0–10 verbal rating scale (VRS). Pulmonary function (FEV1, FVC, PEFR) and oxygen saturation were also measured. Results Patients who received CSL 30 had lower post-operative pain scores than CSL 10 (ANCOVA—mean difference = 0.47, 95 % CI 0.11–0.83, P  = 0.01). Post-operative pain VRS was lower in CSL30 than CSL10 at 48 h (mean difference 0.56, 95 % CI 0.04–1.09, P  = 0.036). Patients in CSL30 reported shoulder tip pain less frequently than those in CSL10 (30.4 vs. 43.9 % of assessments, P  = 0.03, OR 0.58) but reported wound pain more frequently 39.0 vs. 24.2 %, P  = 0.01, OR 2.0). Indices of pulmonary function did not differ between groups at any time. Conclusions Liberal compared to restrictive administration of i.v. crystalloid is associated with a clinical modest reduction in pain. Pulmonary dysfunction was not increased with liberal fluid administration.