In this paper we estimate systematic risk of the Slovak unquoted agricultural farms – agricultural cooperatives and companies, in the period of 2009-2012. An alternative Markowitz portfolio theory approach was applied. As a measure of the systematic risk, we used return on equity (ROE). Based on the dataset of 996 farms over years 2009-2012, the Slovak farm average ROE reached 0.048% and systematic risk 3%. The Slovak agricultural farms displayed low profitability. The average ROE was higher and systematic risk indicator was lower for agricultural companies than for agricultural production cooperatives. Thus the agricultural companies could be more attractive for investors.