A field experiment was conducted to study effects of different rice-based cropping systems on diseases, pests and weed (DPW) hazards and yield of rice. The experiment included four treatments: conventional rice farming system (CR) as control, conventional Oenanthe javanica farming system (CO), conventional intercropping of rice with Oenanthe javanica (CRO) and organic intercropping of rice with Oenanthe javanica (ORO). Results show that DPW hazards were significantly lower in CRO and ORO than CR. CRO and ORO treatments presented, respectively, 45.12% and 47.58% lower rice leaf blast infected hills than CR during the early tillering stage, 41.38% and 6.80% lower during the late tillering stage and 69.77% and 44.39% lower at the booting stage. Planthopper numbers in CRO and ORO were, respectively, 82.80% and 78.08% lower than CR during the maturity stage. Weed density in CRO and ORO treatments was 48.36% and 39.34% lower than CR, respectively. Land equivalent ratios for CRO and ORO treatments were 1.11 and 1.33, respectively, compared to the CR treatment, while yields were 11.31% and 33.11% higher than CR. In summary, intercropping rice with Oenanthe javanica, especially under organic conditions, plays a significant role in rice cultivation.