This Thematic Issue of Biomass Conversion and Biorefinery (BCAB) on sustainable management of organic waste includes forty-two papers presented at the HERAKLION 2019 7th International Conference on Sustainable Solid Waste Management (http://www.heraklion2019.uest.gr). The Conference took place in Heraklion, Crete, in Greece at the end of June 2019 (26–29 June). We were happy that more than 700 participants from all over the world flew to Crete to join us. Apart from the rich agenda including more than 500 presentations within the 26 sessions with oral presentations, the extensive poster sessions, and the splendid social events, the conference also included an international summer school—extensive training on solid waste management and circular economy, as well as several site visits to local agriculture and livestock production facilities applying circular economy in practice.

High-quality papers of the HERAKLION 2019 Conference related mainly to sustainable management of organic waste were selected by the Scientific Committee to be included after improvement and normal review process in the present BCAB Thematic Issue. The papers cover a wide range of subjects, including anaerobic digestion, circular economy initiatives for different biodegradable feedstocks (food waste, agricultural waste, etc.), biotechnology and biorefineries, thermal technologies, biofuels. The papers present significant research initiatives from many different countries so as to strengthen and promote circular bioeconomy that is expected to play an important role in everyday life very soon decreasing the dependence on fossils fuels and offering new opportunities for the production of high added value products from different organic substrates with multiple applications.

Last but not least, the Guest Editors would like thank the Journal that provided us with the opportunity to work for this Thematic Issue including high-quality papers from this conference event on sustainable solid waste management. We are also happy that another Thematic Issue of the Journal will be prepared with relevant high-quality papers of the next conference of this conference series, THESSALONIKI 2021 Conference (http://thessaloniki2021.uest.gr), that will take place virtually from 23 to 26 June 2021 due to the COVID-19 restrictions.