In order to study of forage yield, and land equivalent ratio efficiency in pure stands and mix crop of red clover and tall fescue, 7 ecotypes of red clover (Trifolium pratense) and 1 ecotype of tall fescue (Festuca arundinacea) were sown in pure stand and 50% clover+50% tall fescue mix cropping using complete block design with 3 replications during 2004 to 2006 in northern Alborz rangelands, Iran. Data were collected and analyzed for each year and combined over two years, using split plot in time design with years as sub plot. Duncan multiple test were used for comparison among treatments. Efficiency of mix cropping was assessed by land equivalent ratio. Results showed significant differences between pure stand and mixture in the first year, but no significant differences were observed in the second year. The forage production of pure clover, pure fescue and mix crop were 5199, 2078 and 2981 Kg/h in the first year and 3059, 3014 and 3024 in the second year, respectively. Result indicated that tall fescue growth was lower than clover in the first year, but it was dominant to clover in the second year. For pure clover, ecotypes of 1568, 1753, 618 and 2086 with average values of 4300 to 4800 kg/h had higher annual production over two years. The ecotype 1753 originated from Orumieh; with having prostrate growth habit was recognized as the best one for pasture regeneration in northern Alborz rangelands. The mix cropping of clover (2086) and tall fescue, with average values of 4047 and 3987 kg/h forage yield and with average values of 1.09 and 1.18 land equivalent ratios for the first and second year, respectively, introduced for mix cropping with tall fescue.