The company did not disclose the deal value.
The deal comes as demand for mobile data services explodes and wireless carriers try to keep pace with that growth.
ComScore, a provider of data that helps track Internet and mobile trends, expects the deal to add about $4 million to its 2010 revenue, with similar profitability margins to the rest of its business.
The transaction will add to 2010 GAAP and non-GAAP net income, the company said.
The acquisition will be integrated into ComScore's telecom and wireless practice. Nabil Taleb, CEO of Nexius, will join ComScore's senior management team and be named executive vice president of ComScore Wireless Solutions.
Customers of ComScore, which competes with Nielsen Online, have included AOL Inc, Procter & Gamble Co, Microsoft Corp, Yahoo Inc and Google Inc.
ComScore shares closed at $16.86 Thursday on Nasdaq.
(Reporting by S. John Tilak in Bangalore; Editing by Jarshad Kakkrakandy)