Swiss chard is widely cultivated and one of the most nutritious vegetable in the world. It is highly appreciated in many parts of the world for its year-round availability, low-cost and wide use in many traditional dishes as well as more robust and easier to grow. In Ethiopia, it ranked fourth among cool-season leaf-vegetables based on area coverage and production in quintals next to Ethiopian cabbage, head cabbage and lettuce. However, little research effort was made before to enhance its productivity. The crop is neglected in relation to research. Furthermore, the information on the use and application of biochar and mineral NPS fertilizer rate for Swiss chard is lacking in the study area. Hence, this study was conducted with the objective of assessing the effect of biochar and NPS fertilizer on growth and yield of Swiss chard and soil properties in North Ari, Southern Ethiopia. Therefore, a field experiment was conducted during the 2022/2023 in North Ari District to assess the effects of biochar (10,20 and 30 t/ha) and NPS fertilizer rate (0, 50, 100,150 and 200 kg N ha-1 ) on growth and yield components of Swiss chard. The experiment was laid out in a randomized complete block design (RCBD) of factorial arrangement with three replications where, Ford Hook Giant variety of Swiss chard was used as a test crop. Results indicated that biochar and NPS fertilizer significantly (P < 0.05) influenced days to first harvest of Swiss chard in their main effects. The interaction effects of biochar and NPS fertilizer influenced plant height, leaf number, and leaf fresh weight of Swiss chard highly significantly (P < 0.01). Accordingly, the highest leaf number per plant (14.83), total number of leaves harvested per plant (12.00) and average leaf fresh weight (93.37g) of Swiss chard plant were recorded in response to the application of 200 kg N ha-1 and 30 t/ha biochar. The highest leaf length per plant (67.30 cm), marketable (36.54 t ha-1 ) and total leaf fresh yields (37.31t ha-1 ) of Swiss chard were recorded by application of 30 t/ha biochar with 100 kg NPS ha-1. As the results were limited to one location and season, repetition of the study in multi-location and season is also recommended.