This paper reports a case study of nominalization in four journal articles in biology, economics, social science, and language written in Indonesian. In order to know the patterns of nominalization in the four articles, the clauses containing nominalization were identified, seen from whether the lexical items in the four articles were realized congruently or incongruently. The data analysis shows that nominalization in the four articles is realized by means of grammatical metaphor where verbs, adjectives, adverbs, modals, and conjunctions are metaphorically shifted to nouns. From the total lexical items incongruently employed in the four articles, the nominalization amounts to 97.6 % in Biology Text, 95.2 % in Economics Text, 96 % in Social Science Text, and 97.8 % in Language Text. The findings about nominalization are not only ideationally significant to the abstraction of real world (Martin, 1991, 1993a, 1993b; Halliday, 1993a, 1993b, 1998), but also textually significant to the text structure of the articles (Hyland, 2008).

Keywords: Nominalization, scientific text, grammatical metaphor, congruent, incongruent