This two-year research aimed to evaluate the efficacy of chemical preparations and the resistance of tomato cultivars (Amati and Bella) against the Phytophthora infestans pathogen causing fruit blight. Fungicides, including Metalaxyl, Azoxystrobin, Mancozeb, and Copper, were tested in seven combinations, and disease assessments were conducted using the McKinney Index. Results from 2021 and 2022 consistently demonstrated that the combination of Azoxystrobin and Metalaxyl exhibited the highest efficiency in protecting both cultivars against Phytophthora infestans, with infection rates as low as 5.30% and 4.43%, respectively. In addition to fungicide effectiveness, cultivar resistance analysis revealed that Bella consistently displayed higher sustainability to the pathogen compared to Amati, with infection rates ranging from 4.43% to 6.30% for Bella, compared to 5.30% to 7.03% for Amati. This enhanced resistance in Bella was attributed to its smaller vegetative mass. The study underscores the importance of meticulous systemic fungicide use to prevent the development of pathogen resistance. Furthermore, the research recommends adjusting the frequency of sprayings based on climatic conditions to optimize blight management strategies. This research provides valuable insights into effective blight management strategies, highlighting specific fungicide combinations, and emphasizing the resistance characteristics of tomato cultivars. These findings contribute to the development of sustainable practices for protecting tomatoes against Phytophthora infestans, ultimately aiding in the cultivation of more resilient and disease-resistant tomato crops.