Striga is an obligate parasitic weed attacking cereal crops in Subsaharan Africa. In Western Kenya, it is identified by farmers as their major pest problem in maize. A new technology, consisting of seed coating of herbicide tolerant maize varieties, has prove to be very effective in farmer fields. To bring this technology to the farmer, a sustainable delivery system needs to be developed, preferably through the private sector. To help of the seed companies develop a strategy, the potential market for this technology is hereby calculated, combines different data sources into a Geographic Information System (GIS). Superimposing secondary data, field surveys, agricultural statistics and farmer surveys makes it possible to clearly identify the Striga-prone areas in western Kenya. According to the analysis, the area has 212,000 ha in maize annually, with a population of 5.9 million people and a maize production of 480,000 kg, or 81 kg/person. Population density is high at 359 people/km2. A farmer survey reveals that 70% of farmers in this zone have Striga in their fields. Contingent valuation methods indicate that farmers' would be willing to buy on average 3.67 kg of the new seed each. This translates into a potential demand of 3,400 to 5,200 tons annually. Similar calculations, but based on much less precise data and expert opinion, not farmer surveys, estimate the potential market for herbicide tolerant maize against Striga at 64,600 tons annually, with an estimated value of $129 million.