The study was conducted to know the exact time of layering and IBA concentration on rooting and establishment of air layers of Guava cv. Lalit under Southern Transitional Zone of Karnataka during the year 2019-2020 at Guava Mother Block, Organic Farming Research Centre and Department of Horticulture, College of Agriculture, University of Agriculture and Horticulture Sciences, Shivamogga. The experiment was laid out in Factorial Randomized Completely Block Design having sixteen treatment combinations with four repetitions. The study revealed that, among different time of layering, the minimum number of days for root initiation (38.62), maximum rooting percentage (71.75), maximum number of primary and secondary roots per layer (17.00 and 7.39 respectively), length and diameter of longest root per layer (9.51 cm and 0.84 mm respectively), fresh and dry weight of roots (2.35 g and 0.80 g respectively) observed best in the layers prepared on first fortnight of June. Among different concentration of IBA, the minimum number of days for root initiation (36.75), maximum rooting percentage (77.19) maximum number of primary and secondary roots per layer (18.91 and 8.93 respectively), length and diameter of longest root per layer (10.16 cm and 0.85 mm respectively), fresh and dry weight of roots (2.56 g and 0.98 g respectively) was recorded best with 4500 ppm IBA concentration. On the basis of the results obtained in the present investigation, air layering performed during first fortnight of June, treated with 4500 ppm IBA concentration have been found significantly superior compared to other treatments under Southern Transitional Zone of Karnataka.