Kostadin Sirleshtov > CMS > Sofia, Bulgaria > Lawyer Profile

14 Tsar Osvoboditel Blvd.
1000 SOFIA

Work Department

Energy, Projects, Construction (EPC)


Office Managing Partner of CMS Sofia, CEE Head of EPC and CEE Energy Sector Head


Kostadin Sirleshtov is Managing Partner of CMS Sofia and Head of the Energy, Projects and Construction (EPC) practice for Central and Eastern Europe and for Bulgaria.

His area of expertise is in conventional power, nuclear, electricity, renewables, oil & gas, infrastructure, projects, PPP, public procurement, underground resources. He has worked as the Chief of the Minister’s cabinet for the Ministry of Energy and Energy Resources 2002-2004 and Chief of Minister’s cabinet in the Ministry of Defence 2005-2007.  As part of the team at the Ministry of Energy and Energy Resources Kostadin was a member of the working group, which prepared the current energy legislation of Bulgaria, including the Energy Act 2003 and the Energy Efficiency Act 2004. 

Kostadin has vast experience in the conventional power and electricity sector. He has represented clients, including renewables organisations, in negotiations with the Bulgarian Government, the National Electricity Company and the Electricity Transmission System Operator. He has also advised major international oil & gas prospecting and exploration companies in Bulgaria on various onshore and offshore projects. In addition, he is particularly focused on advising renewables companies (in relation to wind, hydro, solar and biomass projects) on the development, operation and/or sale of their projects in Bulgaria, including on litigation matters.

Kostadin is an honorary advisor to the Deputy Chairman to the Energy Commission to the Bulgarian Parliament on legislative reform matters.


English, Bulgaria


Sofia Bar Association


Sofia University “St. Kliment Ohridski”

Lawyer Rankings

Bulgaria > Projects and PPP

(Leading individuals)

Kostadin SirleshtovCMS

CMS advises major energy producers, including electricity suppliers, upstream oil and gas companies, and energy investors, on large-scale projects and on their participation in bidding and tendering processes. The firm has advised participants in major tender procedures to build airports, roads, railways, and pipelines. Kostadin Sirleshtov, joint practice head, also leads the firm’s energy practice, while co-head Dimitar Zwiatkow has experience in public procurement procedures, structuring of consortia, and advising winning bidders on the implementation of their projects. Denitsa Dudevska and Antonia Kehayova are key contacts for mining and real estate projects, respectively.

Bulgaria > Energy and natural resources

(Leading individuals)

Kostadin SirleshtovCMS

The team at CMS draws on its ‘long-term experience’ to advise clients on the full spectrum of energy and natural resources work, including nuclear and conventional energy production, oil and gas exploration, renewable energy, waste management, and regulatory consultancy and litigation. The team is especially prominent in exploration, having assisted Shell, SPM, Repsol and Petroceltic with obtaining onshore and offshore licences. The firm’s strong corporate and commercial practice also allows the team to advise on financing, agreements and restructurings of energy projects. The practice is jointly led by Kostadin Sirleshtov, who is a former board member of several key energy companies and highly rated by peers in the sector, and Dimitar Zwiatkow, who specialises in the financing and real estate aspects of projects.