This study aims to examine nominal vocatives in Twitter through the analysis of 1500 posts extracted from the accounts of five well-known female and male rappers. From this total, a sample of 550 vocatives were analysed. Attention is paid to their frequency, class, position, type of clause and the polarity in which they occur, and the pragmatic functions they express. The factor of gender is also investigated. The analysis reveals that those posting to these Twitter accounts make use of a very large and varied repertoire of nominal vocatives. The group of familiarisers clearly prevails over other categories of vocatives and this high frequency of familiarisers contrasts to the situation in spontaneous conversations where first names tend to be the most common. Vocatives in final position clearly prevail over initial and medial position. Besides, Twitter posts containing nominal vocatives in final position tend to be short while those in initial position are far longer. Polarity does not seem to have a strong influence. Some differences, however, are also observed according to the use of nominal vocatives with respect to gender. As in spontaneous conversation, vocatives in Twitter generally serve to strengthen social relationships (creating solidarity, complimenting, expressing appreciation, reinforcing the group identity) while discourse-oriented functions relating to topic and turn management are not so common.