Objective : The aim of the present study was to evaluate the clinical and microbial efficacy of local delivery of minocycline gel 2% as an adjunctive therapy to SRP compared with SRP alone in chronic periodontitis patients. Subject and methods: A total of twenty patients with moderate chronic periodontitis were included in the present study. The selected patients were divided in two groups (group I and group II) and every group was divided according to the split-mouth design into applied and control side. All patients were subjected to conventional periodontal therapy (SRP) except applied side of group II . moreover; the applied side of each group was subjected to sub gingival delivery of minocycline gel and control side was subjected to SRP, the patients followed up for three weeks.  Clinical parameters used in this study included; plaque index (PI), gingival index (GI),Bleeding on probing (BOP), probing pocket depth (PPD) and clinical attachment level (CAL). These parameters were measured before starting the treatment and after treatment regimen (3weeks). sub gingival plaque sample were taken before starting the treatment and also at the end of the study after three  weeks using sterile curette and delivered in a sterile tube containing a suitable transport media and analyzed for isolation of p.intermedia and p.gingivalis. The results : the clinical results of both groups showed statistically significant improvement for both applied and control side which more higher in applied side of group I for all clinical parameters and results of microbial evaluation showed that, p.intermedia and     p.gingivalis count decreased significantly after treatment in both groups especially in applied side of group I Conclusion: Scaling and root planning (SRP) was effective in improving clinical and microbiological parameters in patients suffering from moderate chronic periodontitis, Local use of minocycline gel as an adjunct to SRP has resulted in significant additional improvement in the clinical conditions of moderate chronic periodontitis patients when compared with SRP alone,  Minocycline application results in sufficient reduction in bacterial challenge especially when combined with SRP. Keywords: Minocycline gel; chronic periodontitis; microbiology.