CO2-insufflation and electrocoagulation were advanced as causative factors of postsurgical adhesions. We assumed that severe tissue reaction due to electrocoagulation might obscure CO2-insufflation impact on adhesion formation. Therefore, the purpose of this study was to evaluate the effects and interactions of surgical trauma and CO2-insufflation on adhesion formation. Prospective-randomized study with 60 rats, equally divided into 3 groups. In the control group, the sidewall adhesion model was induced by monopolar coagulation of the uterine horn and ipsilateral parietal peritoneum and by mechanical damaging - in the opposite side through open laparoscopy without CO2-insufflation. In two other groups, CO2 was insufflated for 60 min at 15 cm of water, either before or after the sidewall model-induction. Parameters of sidewall and lesion site adhesions of parietal peritoneum and uterine horns were evaluated by scoring system and analyzed by two-way ANOVA with Bonferroni posttests, one-way ANOVA Student-Newman-Keuls multiple comparisons test, as well as by two-tailed unpaired Mann-Whitney test. Monopolar coagulation significantly increased peritoneal lesion site adhesion scores, as compared with the scores for mechanical damaging (p=0.0001). Visceral peritoneal lesion sites were more predisposed to adhesion formation than parietal peritoneal lesion sites (p=0.0009), whereas CO2 did not affect parameters of either sidewall or peritoneal lesion site adhesions, regardless of the insufflation mode (p>0.05). The data suggest that both surgical trauma and peritoneal lesion sites had a substantial impact on adhesion formation, whereas CO2 did not interfere with adhesion parameters irrespective of its insufflation mode. These findings may improve our insights into adhesion formation pathophysiology and open new perspectives in developing future adhesion prevention strategies.