I will report on the latest results of our programmes to monitor 
extrasolar planetary transits. We include planets confirmed by radial 
velocities as well as promising candidates. The observations are carried out 
at 8m -class telescopes located in Chile, allowing us to obtain very precise 
transit lightcurves. For the known planets, we measure accurate orbital 
periods and planetary radii. For the new candidates, we discuss the different 
possibilities (blends, false positives, planets), chosing the best candidates 
for radial velocity follow-up.