A longitudinal study was conducted on 106 patients attending a dental school and undergoing periodontal treatment, to assess the relationship between some commonly used periodontal indices and the time taken to treat periodontal disease. The data were analysed by assessing the times taken for examination motivation, scaling and surgery for persons with ranges of indices such as D.I., C.I., O.H.I., G.P.I. (Ging), G.P.I. (Perio), G.P.I. (Comp) and P.I. A one-way analysis of variance was carried out to test the significance of trends. Next, a Spearman correlation coefficient was calculated for each index and its components and treatment time. The index which correlated most closely with examination time was the P.I. The G.P.I. (Ging) was the best predictor of motivation time and three indices, C.I., G.P.I. (Perio) and P.I. correlated significantly with scaling times. The P.I. and G.P.I. (Perio) correlated with surgery time. By converting periodontal indices into treatment times, planners can estimate with a fair degree of accuracy the time and resources required to carry out periodontal treatment for a population.