Tigo, South Asia's first mobile phone operator, now has a market share of 21 percent in Sri Lanka and had 2.
25 million subscribers by September 2009.
"We also plan to invest in this company to ensure that it has the dynamism to take the leading position in the market in the next few years¦," Etisalat chairman, Mohammed Hassan Omran said in a statement.
"The acquisition promises attractive returns as the Sri Lankan Government is increasing its effort to promote foreign investment in all sectors.
"
Etisala said mobile penetration in Sri Lanka was 52 percent in March 2009, and Tigo Sri Lanka also had a license to offer third generation mobile services.
Sri Lanka's mobile phones have been caught in a tough price-war but telecom analysts have said that the Tigo network is leanly run.
Etisalat said it had investments in Pakistan, Afghanistan, Indonesia and India, which were among the fastest growing markets in the telecommunications sector.
Millicom said Etisalat had paid 155 mi