After a timid start 15 years ago, the Balkan country is now a hub for information technology and back-office outsourcing.
As well as call centres, firms offering software and web development, data services and technical support are attracting business from foreign companies finding it cheaper to sub-contract abroad.
Growth in the sector has rocketed at up to 25 per cent annually in recent years, helping Bulgaria's economy to rebound to growth of 0.9 per cent in 2013 after shrinking 5.0 per cent in 2009.
"Bulgaria ranks third worldwide in the number of certified software engineers and first in the number of IT specialists per capita," Deputy Economy Minister Krasin Dimitrov told a recent outsourcing conference in Sofia.
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According to outsourcing association chairman Stefan Bumov, the burgeoning industry has the potential to employ two or even three times more people -- a promising prospect in a country where more than a quarter of youngsters are unemployed.
His company Sofica Group started with 30 people in 2007 and has grown to become the largest home-grown player in the sector, with more than 900 employees.
In March it was snapped up by US-based firm Teletech, and other foreign outsourcing giants have also bought local firms.
Coca Cola HBC opened its own back-office services centre in Sofia in 2005 and is now serving 26 countries from here. It was followed by Hewlett-Packard, which opened a global delivery centre in 2006 and picked Bulgaria as one of its six "delivery hubs" in 2010.
Bulgaria ranked 17th in the latest A T Kerney global services location index, while India usually takes the top spot.
Exports say Bulgaria's sector needs government help to develop a more aggressive marketing strategy and raise its profile.