The paper presents an introduction, in which is highlighted the importance of the time series analysis in the statistics studies, due to the multitude of information that can be detached from their calculation, the mode in which are used the statistical and econometrical analysis methods of the time series components in the foreign and Romanian specialized literature, as the statistical methodology used for the characterization of the tourism activity in Romania, in the period 1997-2011, consisting of: average ranks method used for the bi-criteria hierarchy of the territorial series, the time series analysis methods namely: graphical method, average indicators analysis of series comprised of total tourist arrivals, foreign and Romanian tourist arrivals, statistical methods of time series adjustment, grouped in two categories: mechanical methods (moving averages method, average spore method and average index method) and analytical methods (linear function and 2^nd degree parabola) and statistical forecasting based on the above mentioned methods. Indicators taken in study were the tourist arrivals and overnight stays on total country, on foreign and Romanian tourists and, on their basis, it could be calculated and analyzed also the average length of stay. Considered horizon of prognosis was a medium one that is until the year 2015. Data source is represented by Anuarul statistic al României, published by the National Institute of Statistics.