Introduction: The appearance of the Argentine Vegan Union in 2000 laid the foundations for strict vegetarianism in Argentina. Objective: The objective of this study was to describe aspects associated with the initiation and transition from omnivorous to vegetarian diet in the population over 18 years of Argentina. Materials and methods: A quantitative, descriptive, observational, retrospective, cross-sectional study was carried out. An online questionnaire aimed at strict vegetarians was used as an instrument. The sample was 121 people. A univariate descriptive analysis of the data and content analysis of the open questions of the form was carried out. Results: The 51.2% of the respondents (n = 62) were between 21-30 years old, followed by 27.3% of respondents (n = 33) with an age range of 31-40 years. There were significant differences by gender, 77.6% (n = 94) belonged to the female gender. A total of 58 people agree that strict vegetarianism is a food and ethical issue of respect for animals. A total of 58.6% (n = 71) made a gradual transition to diet, while 41.4% (n = 50) made a sudden transition. 96.6% (n = 117) reported having sufficient income to purchase food for this diet and 62.8% mentioned that a plant-based diet is less expensive than an omnivorous one. 24.6% (n = 31) stated that they produce their food at home. 95.86% (n = 116) of the respondents prepare their own meals. It was observed that 74.1% (n = 86) highlighted economic reasons in their answers. On the other hand, 82.6% (n = 100) of those surveyed stated that they bought ready-made food, 70% (n = 70) due to lack of time, comfort or pleasure. Conclusion: This research allowed us to recognize within the study population groups susceptible to nutritional deficits during the initiation and transition to vegetarianism if they do not receive adequate accompaniment by nutrition professionals. Likewise, this study made it possible to establish lines of research on a population that has grown notably in recent years. Keywords: Strict vegetarianism; transition; youth; adults.