Excise duties on roll-your-own (RYO) tobacco, which are generally based on RYO cigarettes containing 1 g of tobacco, are lower than duties on factory-made (FM) cigarettes. This provides a price incentive for smokers to switch to RYO, the use of which is increasing across Europe. To effectively approximate duties on the two types of products, accurate data on the weight of RYO cigarettes are required. We provide updated information on RYO use and RYO cigarette weight across Europe. From a representative face-to-face survey conducted in 2010 in 18 European countries (Albania, Austria, Bulgaria, Czech Republic, Croatia, England, Finland, France, Greece, Hungary, Ireland, Italy, Latvia, Poland, Portugal, Romania, Spain and Sweden), we considered data from 5158 current smokers aged 15 years or above, with available information on daily consumption of FM and RYO cigarettes separately. In Europe, 10.4% of current smokers (12.9% of men and 7.5% of women) were 'predominant' RYO users (i.e. >50% of cigarettes smoked). This proportion was highest in England (27.3%), France (16.5%) and Finland (13.6%). The median weight of one RYO cigarette is 0.75 g (based on 192 smokers consuming exclusively RYO cigarettes). The proportion of RYO smokers is substantial in several European countries. Our finding on the weight of RYO cigarettes is consistent with the scientific literature and industry documents showing that the weight of RYO cigarettes is substantially lower than that of FM ones. Basing excise duties on RYO on an average cigarette weight of 0.75 g rather than 1 g would help increase the excise levels to those on FM cigarettes.