Effect of the amount of fertilizer, plant density, and harvesting time on the production of tobacco leaf protein and fresh biomass was investigated. Flue-cured tobacco(M tabacum, L., cv. NC 82) seedlings were transplanted in the field dressed 200kg N per ha at 1$ imes$105, 3$ imes$105, 5$ imes$105, 7$ imes$105 plants per ha, and were harvested at the time when 6 and 10 weeks after transplanting, respectively. Harvest at 10 weeks after transplanting increased greatly number of leaves per plant and fresh weight of a plant, Precentage of senescent leaf weight, but significantly decreased fresh weight of a leaf and total protein contents g-1 fresh weight of leaf and stalk over the amount obtained from the harvest at 6 weeks after transplanting. Also, fresh leaf numbers of a plant, fresh weight of a leaf and of a plant, and total protein contents g-1 fresh weight of biomass were more decreased, but percentage of senescent leaf weight were remarkably increased under higher plant density. Therefore, it was seemed that harvesting at 6 weeks after transplanting under 1$ imes$105 plant density per ha is more effective for producing higher yield of biomass and protein per plant than 10 weeks harvesting with 7$ imes$105 population per ha. A trend was observed that biomass and protein yields per ha are positively correlated with plant population. Biomass yield per ha was the greatest at 7$ imes$105 density(80.5t), but the peak of protein yield was at the near of 5$ imes$105 population(2454kg as total protein) per ha on the regression curve. It was assumed that if tobacco plants are transplanted under 5$ imes$105 plant density at the mid of May, and thereafter harvest at 6 weeks repeatedly during the growing season, it is possible to harvest 2~3 times per year, and to yield more 6.024kg of protein and over 140me1ric tons of fresh biomass ha 1 year 1 statistically in the korea tobacco growing regions.