Resumen: Objective: To analyze the impact of front-of-pack warning labeling (FOP-L) on food purchase patterns in Chilean families with children under 14 years of age after the implementation of the Law on nutritional labeling in Chile. Methods: A cross-sectional study in 468 parents/tutors from 11 schools in Santiago. The questionnaire investigated FOP-L perception, food purchase patterns, and the influence of children on the selection of foods purchased by the family. Results: Mostly mothers are responsible for household food purchases (62.0 %). Parents with a higher schooling level had a greater knowledge of the regulation (p < 0.05). In all, 66.3 % did not consider label information before the law was implemented. The FOP-L considered most important was “High in sugars” (18.0 %); 49.5 % stopped buying some foods due to the presence of a FOP-L; 75.0 % of parents reported that their children accompanied them at the supermarket. A lower probability of food purchase pattern change was observed in families that did not consider the FOP-L an important tool (OR: 5.85; p < 0.001), did not understand the meaning of the FOP-L (OR: 2.99; p = 0.020), had not the habit of reading nutritional labeling prior to law implementation (OR: 2.63; p < 0.001), or had a child who requested specific foods (OR: 2.91; p = 0.009). Conclusion: Factors associated with buying food with FOP-L included: Not considering their presence important, lack of understanding, not having the habit of reading labels on packaged foods prior to the Law, and having a child requesting food at the supermarket.