No-till alfalfa renovation in semiarid regions has been very limited due to competition from existing vegetation for light and water. This study was conducted to determine optimum vegetation control strategies and moisture conditions on establishment and yield of alfalfa. The effects of timing of glyphosate [N-(phosphonomethyl)glycine] application, alfalfa cultivars (including a glyphosate-tolerant experimental line) and five irrigation levels were investigated at Bozeman, MT in an old and thin alfalfa stand under sub irrigated condition. During establishment year, applying glyphosate four weeks (NT4) before planting resulted in more plant population and yield than delaying two weeks or spraying and seeding the same day. Alfalfa yield of NT4 was also higher than a conventionally-tilled seedbed. Alfalfa yield during establishment year responded significantly to irrigation level. Post-emergent weed control with glyphosate over a glyphosate-tolerant alfalfa appears to be effective for no-till establishment. These results indicate that delaying planting four weeks after spraying with glyphosate and controlled irrigation is a promising no-till alfalfa planting system that could be implemented in western Montana.