The objective of this thesis is to propose an online marketing strategy for the Divadlo.cz web portal, which is currently undergoing a complete redesign including the extension of functions and services provided to its users. The proposed mix of marketing activities should help to increase the target groups' awareness of news on the web and provide the increase of the targeted visit rate. At the same time I focused on the possibilities of the increase of the web conversion ratio and, on the basis of the analyses and user testing performed, I proposed some changes on the web, which will contribute to the creation of more user-friendly environment and will facilitate the achievement of the web's objectives. Owing to the fact that the operator of the portal is the Arts Institute - Theatre Institute, which is a state-funded organization founded by the Ministry of Culture of the Czech Republic, I selected such marketing methods which least burden the budget and their staffing can be mostly provided in-house. The elaboration of this thesis was primarily based on my own knowledge and experience, obtained by several years of self-study and work in a company, which engages in web design and Internet marketing. The entire thesis is divided into two main parts; the first, theoretical part deals with the Internet marketing itself and its selected tools, which can be utilized during the creation of online marketing strategy of the web in the non-profit sector. In the other, principal part I focus exclusively on the Divadlo.cz portal: first I subject the portal to web analyses and user testing, and in the conclusion I propose the specific marketing strategy for the increase of the web visit rate, divided into the following components: subject, time, finances and personnel.