The purposes of this study were to 1) Analyze the costs in the production of hydroponic vegetables in Nakornpathom Province 2) Compare the costs and returns received from growing hydroponic vegetables in Nakornpathom Province. A qualitative research and quantitative. research tools use in-depth interview assort purposive samling of 3 farmers that has grown hydroponic vegetables in Nakhon Pathom province. The first farmer is hydroponic vegetable garden Ban Thung Rang Thian, Wang Taku Subdistrict, Mueang District, Nakhon Pathom Province. The second farmer is Ban Rai Suan Farm Suk, Thap Luang Subdistrict, Mueang District, Nakhon Pathom Province. And the third farmer is Ban Suan Melon Nong Pak Long Subdistrict, Mueang District, Nakhon Pathom Province. The data were analyzed in terms of cost structure, revenue and return from investing.

              Arter studying and analyzing the cost structure, revenue and return from investing, the findings revealed that, the first farmer has the total of cost  structure 705,200 Baht per year. which gained return/revenue of 1,140,000 Baht per year. has net profit equal to 434,800 Baht per year and the return from investing a equal to 222.97%. The second farmer has the total of cost  structure 727,850 Baht per year. which gained return/revenue of 2,280,000 Baht per year. has net profit equal to 1,552,150 Baht per year and the return from investing a  equal to 234.46%. The third farmer has the total of cost  structure 141,457 Baht per year. which gained return/revenue of 345,000 Baht per year. has net profit equal to 203,543 Baht per year and the return from investing a  equal to 189.34%.

              The knowledge gained from this research is to analyze the cost of growing hydroponic vegetables to know both the profits and the rate of return on investment received from growing hydroponic vegetables.