New photometric follow-up observations of transitting 'hot Jupiters' TrES-3b and Qatar-1b are presented. Weighted mean values of the solutions of light curves in R-filter for both planetary systems are reported and compared with the previous results. The transit light curves were analysed using the WINFITTER code. The physical properties of the planets were estimated. The planet radii are found to be R-p = 1.381 +/- 0.033R(J) for TrES-3b and R-p = 1.142 +/- 0.025R(J) for Qatar-1b. Transit times and their uncertainties were also determined and a new linear ephemeris was computed for both systems. Analysis of transit times showed that a significant signal could not be determined for TrES-3b, while weak evidence was found for Qatar-1b, which might be tested using more precise future transit times. (C) 2017 Elsevier B.V. All rights reserved.