Microbial oils are lipids formed by various microorganisms. Microorganisms that are able to accumulate lipids more than 20% of their biomass are named as "oleaginous microorganisms". These oleaginous microorganisms such as bacteria, yeasts, moulds, and algae are able to accumulate SCO (Single Cell Oil) during secondary metabolic growth. Rhodosporidium toruloides Y27012 is an oleaginous red yeast, which accumulates both lipids and carotenoids by using different carbon and nitrogen sources. The aim of this present study was to investigate the effects of different nitrogen, carbon sources, C/N (carbon to nitrogen) ratios, and some additives on cell growth, lipid accumulation and carotenoids production by R. toruloides Y27012. The maximum biomass, lipid accumulation and carotenoids yield were observed with yeast extract and glucose when used as nitrogen and carbon sources, respectively. R. toruloides Y27012 gave the highest values of both biomass and lipid content (53.41±0.93 g/L, 49.83±2.53 %) at C/N ratio of 60, whereas higher nitrogen levels such as C/N ratio of 20 enhanced the production of carotenoids (1001.51±17.87 µg/g). Among the tested additives, ethanol at 10 g/L increased the carotenoids yield up to 1732.17±39.45 µg/g comparing with the control sample at 1001.51±17.87 µg/g. Biomass and lipid contents were found to be higher when acetic acid at 5 g/L was added as an activator (41.97±1.02 g/L, 61.27%±1.77 g/L, respectively). Furthermore, optimization studies for lipid and carotenoids production from R. toruloides Y27012 could be achieved and also cost of fermentation could be reduced by using agro-industrial wastes as an alternative cheap carbon and nitrogen sources to produce valueadded metabolites.