The aims of this study, which analyzes the data related to subjects who for the first time turned to a hospital or to a Public Service Dedicated to Drug Addicts or to a Community Mental Health Center for problems related to pathological gambling in the metropolitan area of Bologna (Northern Italy) in the period 2000/2015, were: to describe characteristics and problems of pathological gamblers (PGs); to estimate the prevalence of PGs using the capture-recapture method. 495 residents were identified, with an estimate of 1570 PGs and a prevalence of 1.78 per 1000. We highlight a high number of new cases in the period after 2010. Most patients are males, aged from 40 to 50 years, 12% was born abroad, one in three suffers from other mental disorders, 9% has alcohol dependence, 8% drug dependence. We should point out the low level of education and the high presence of unemployed subjects.