The trailswere conducted during two consecutive seasons (2017 - 2018 and 2018-2019) in open field at Siwa Experimental Farm Station, at latitude 29^o 12' N, longitude 25^o 29'E and 18 meters below sea level, Marsa Matrouh Governorate, Egypt, to evaluate the effect of three plant density and spraying of two calcium concentrates on growth, yield and quality of two lettuce types grown at winter seasons. Dark green and Mason cultivars represented of both romaine and iceberg lettuce type were transplanted at plant spacing of 25x20, 25x25 and 25x30 cm to give a plant population about 20, 16 and 13 plants per square meter and treated with 300 or 200 ppm of calcium chelate, as well as control treatment. The results indicated that, in spite of decreasing number of marketable heads per plot, low plant density improved average head weight, head diameter, leaf tip-burn, head compactness, as well as enhancement of nutritional value vs, dry matter, Ascorbic acid, potassium and calcium content. Both calcium treatments have a positive effect on lettuce yield and almost quality characters when compared with control treatment, except, average head weight, head diameter, head compactness, leaf tip-burn and dry matter content, dark green as romaine lettuce type produced highest number of marketable heads per planting area, early yield, highest head of water, ascorbic acid, potassium and calcium content. Egyptian market transplanting showed that romaine lettuce type with high density and calcium foliar spray is recommended.