The 7th International Colloquium on Grammatical Inference (ICGI 2004) was heldintheNationalCentreforScienti?cResearch"Demokritos", Athens, Greece on October 11-13, 2004. ICGI 2004 was the seventh in a series of successful biennial international conferences in the area of grammaticalinference. Previous meetings were held in Essex, UK; Alicante, Spain; Montpellier, France; Ames, Iowa, USA; Lisbon, Portugal; and Amsterdam, The Netherlands. This series of conferences seeks to provide a forum for the presentation and discussion of original research papers on all aspects of grammatical inference. Grammatical inference, the study of learning grammars from data, is an - tablishedresearch?eldinarti?cialintelligence, datingbacktothe1960s, andhas been extensively addressed by researchers in automata theory, language acqui- tion, computational linguistics, machine learning, pattern recognition, compu- tional learning theory and neural networks. ICGI 2004 emphasized the multid- ciplinary natureoftheresearch?eldandthe diversedomains inwhich gramm- ical inference is being applied, such as natural language acquisition, compu- tionalbiology, structuralpatternrecognition, informationretrieval, Webmining, text processing, data compression and adaptive intelligent agents. We received 45 high-quality papers from 19 countries. The papers were - viewed by at least two - in most cases three - reviewers. In addition to the 20 full papers, 8 short papers that received positive comments from the reviewers were accepted, and they appear in a separate section of this volume. The t- ics of the accepted papers vary from theoretical results of learning algorithms to innovative applications of grammatical inference, and from learning several interesting classes of formal grammars to estimations of probabilistic grammars.