The investments in biogas and bio-based fertilisers are an important tool for improving competitiveness and potential to increase production and economic performance of companies. The process of restructuring of the agricultural sector in Bulgaria, which is characterised by a large number of limited-capacity small farms, can be stimulated to diversify business by promoting development of biogas and bio-based fertilisers. This helps to increase the viability of the economy of rural Bulgaria which is currently heavily dependent on agriculture. The purpose of this article is to present and analyse the capabilities and attitudes of farmers to produce biogas and bio-based fertilisers as a precondition for improving competitiveness, achieving higher production and economic performance of farms in the agricultural sector and enhancing viability of rural areas in Bulgaria.