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The impressive protein content and rapid growth of Spirulina in entirely alkaline medium have attracted the attention of both researchers and business men. Spirulina is one of the best solutions for the simple production of proteinuous food supplement. The protein content of Spirulina varies between 50 % and 70%. The present study was conducted to investigate the possibility of producing Spirulina in outdoor cultivation technology using a local product (Trona) as a substitute for the three major ingredients (NaHCO3, Na2CO3 & NaCl) in the Zarrouk's standard culture medium. The standard medium (SM) was prepared from analytical grade chemicals and used as a control. Accordingly, a modified culture medium (MM) was formulated by incorporating Trona (Na2CO3.NaHCO3.2H2O). 400 ml brine sample was taken from Lake Chitu. The sample was filtered, and the SM & MM media, were inoculated in triplicate with the Spirulia contained in the brine. The growth of Spirulina continued for ten days with every 48 h monitoring. The data on Spirulina biomass interms of yield and chlorophyll content were collected. Chemical and microbiogical analyses were done. During the growth cycle, the exponential growth phase was mathematically analyzed. In the scaling-up trial, a plastic dish with a diameter of 60 cm was used in the place of a pond for 7 days. Accordingly, biomass determination, phyico- chmical analysis and sensory evaluation were conducted. The doubling time in the analysis of the exponential growth phase gave close values for both media (SM = 53 h, MM = 51 h). The rest of the data were analyzed and means compared by t-Test using SPSS software at 5% significance level. At the end of the experiment (10th day) the mean value of biomass yield was 823.743 mg/l and 832.498 mg/l for the MM and SM respectively. Cell productivity was 83.221 mg l-1day-1 for the SM and 82.374 mg mgl-1day-1 for the MM. The crude protein content of biomass was 50.53% and to 51.93 % in the MM and SM respectively. The odour of Spirulina in SM was rated 6.333 and that of the MM was rated 5.666, while the taste of the SM was 5.888 and the MM was 5.666. Comparison of the two mean values of yield, proximate analysis and sensory analysis showed that there was no statistically significant difference between the products in the SM and MM. This justifies that Trona can be used in the culture medium to cultivate Spirulina for human consumption. Finally, Spirulina production and processing technology has been outlined. Key words: Culture medium, production, Spirulina, Trona.