Since 2000, in Poland's economy there have been considerable legal, environmental and socio-economic transitions taking place, which influence the profitability of mining companies. Favourable external factors, present in the market for raw materials in the recent years, have led to an increase in the economic efficiency of entities involved in the mining business. This phenomenon is well reflected in indices presented by GUS (the Central Statistical Office) for the entire mining sector. The present paper aims to analyse indices for individual entities in the energy and metal raw material sectors, in order to compare their profitability and operating efficiency, based on economic and financial data available in LEX-Legal and Economy Information Resource. Three basic indices have been used to assess the profitability: - return on sale (ROS), expressed as the relationship between the net profit and revenue on sales of products, goods and materials [GUS]; - return on assets (ROA) - the net profit to overall assets ratio; - return on equity (ROE), understood as the net profit in relation to the own capital. The indicative analysis of mining companies was based on data from the years 2000-2006. It was aimed at comparing the profitability and operating efficiency of individual units, and pointing out the influence of changing market conditions on their activity. Most of the companies analysed took advantage of favourable conditions in the market for raw materials, and, by so doing, improved their economic performance. The current overall ROA index for all analysed companies, proves capabilities of their property to make profits and to ensure creditworthiness (banks expect this index to be 2-6%). However, investing in the mining sector - especially in case of energy raw materials - requires also a long-term development plan to exist for that sector.