Treball final de Grau en Economia. Codi: EC1049. Curs acadèmic 2013-2014 Monday effect consists of fuel price falling between Monday and Sunday, followed by price increases during the following days. It is coincidentally on Monday when the European Commission collects fuel prices data to be able to elaborate statistics. In this essay we have firstly studied which has been the recent evolution of the Monday effect in our country. After that we have analysed the magnitude and the difference of these effect in two different areas, a touristic one (Alicante), and a non-touristic one (Orense), as well as the difference between the average in Spain and Castellon. The results showed us that such strategy is not being carried out during the analysed week, in none of the analysed destinations. Results also proved that it is on Friday when prices increase everywhere, but specially in Castellon.