The present study is to evaluate the smoking cessation therapy of the working team of the Cancer Association and Lung Association of the State of Zurich. Roughly 1/3 of all 913 participants of the therapy from 1984 to July 1990 have responded to the survey. Of these 1/3, more than a quarter did not smoke any more one year after the therapy. An antismoking program with a 1-year smoking cessation rate of 20 to 30% is considered successful in professional circles. The smoking cessation rate of all 913 therapy participants is probably below the 27% obtained in as much as the share of the successful ones among those replying, by experience is bigger than the share of those failling. Also the more precise inquiry in the first 7 therapies of 1990 confirms these findings. There the rate of success is barely 15% after 1 to 1 1/2 year. It cannot be ascertained whether the smoking cessation rate of all therapy courses is that high or only at the time after the program restructurations at the beginning of 1990. Only a precise achievement control can guarantee a consequent and continuous therapy evaluation within the next years.