As compared to organic farming system, conventional farming system relies on higher inputs of synthetic agrochemicals, which may reduce the abundance, diversity, and beneficial effects of plant endophytic fungal communities. This study compares the diversity and abundance of culturable endophytic fungal communities associated with four plant species -corn, tomato, pepper, and watermelon grown in separate organic and conventional fields. In all, 740 fungal isolates were identified, of which 550 were from the organic fields and 190 from the conventional ones. These fungal isolates were grouped into eight orders and 22 species, with the two most abundant species being Trichoderma sp. and Pichia guilliermondi. The fungal species diversity and abundance were both significantly higher in the organic than in the conventional fields. All the isolated endophytic fungi improved tomato plants' shoot growth and biomass significantly, as compared with the water control. Six fungal isolates also exhibited activity that enhanced tomato fruit yields. These results suggest that these endophytic fungi might be a considerable boost to sustainable agricultural production, while also reducing the agricultural application of chemicals and thus benefiting the environment and human health.