ABSTRACT : This study was aimed to compare the clinical effectiveness of ozonated gel and chlorhexidine treatments on gingival crevicular fluid (GCF) volume associated with plaque-induced gingivitis (PIG). Fifty male patients affected with (PIG), (25/group) with an average age of (18-30) years were enrolled throughout the study. They were divided into two groups, (G1) scaling and treated with Chlorhexidine and (G2) scaling and treated with Ozone gel. Patients were instructed to massage their gingiva twice a day for 1 week with the ozonated gel). GCF was collected from four sampling tooth sites by paper strips (PS) at zero-time and day-7. The median values of the GCF volume (µL) at 0-time showed that there were no statistically significant differences among the two groups. However, at day-7 post-treatments Ozone gel group showed significantly lower GCF volume. Treatment for 7 days with Ozone gel was much more efficient in reducing GCF volume (µl) when compared with the Chlorhexidine group