Root knot disease on tomato plants caused by Meloidogyne spp. The current root knot disease control was implemented by means of natural control. Marigolds are plants that secrete a substance on the roots that have a negative effect on Meloidogyne spp. Purpose of this study is to determine the best spacing between tomato plants with marigolds plants to reduce nematodes Meloidogyne spp attack on tomato plants. Experiment using a completely randomized design with four treatments and five replications. Treatment being tested is spacing between tomato plants — marigolds plant as far as 15 cm, 30 cm, 45 cm, and a control (without marigolds). The results showed that there is no root knot on tomato plants if marigolds were planted at a distance of 15 cm or 30 cm of tomato plants, while the spacing of tomatoes — marigolds as far as 45 cm can decrease the percentage of root knot as much as 57.04 percent.