Objective To observe the therapeutic effect of non-surgical treatment on diabetic Chinese with chronic periodontitis. Methods Moderate to advanced chronic periodontitis (CP) was studied in 36 diabetes mellitus (DM) patients classified as 20 with high and fiuctuating blood glucose level (DM-H) and 16 with relatively low and stable blood glucose level (DM-L). 28 non-DM CP patients acted as controls (Non-DM). Plaque index (PH), gingival index (Gl), bleeding on probing (BOP), probing depth (PD) and clinical attachment loss (AL)of all patients were recorded at 6 sites on each tooth at the baseline and 1,3 and 6 months after oral hygiene instruction ( OHI) , scaling and root planing. Results It was found that the short-term effect of non-surgical periodontal procedure had resulted in significant resolution of gingival inflammation and pronounced reduction in pocket depth and gain of attachment loss in both DM and Non-DM CP patients. Conclusion The pilot study suggested that non-surgical periodontal treatment allowed for favorable treatment responses in a group of Chinese diabetic subjects with chronic periodontitis and that their various profiles of blood glucose did not influence the short-term healing response to OHI, scaling and root planning.