In the agreement OTM will print 70,000 gas bills a day and post them to Yorkshire Electricity and Northern Electricity (YENE) customers.
Managing director Kris Prashad said: "Winning this deal will give us the confidence and, hopefully, in the next 12 months people will see that our customer base has increased."
The news comes just months after the firm made a seven-figure investment in two Xerox iGen3 digital presses for its site on Scudamore Road.
Some of its functions from the Leicester site are carried out by its sister location in Swindon. Other customers include Avis, Royal Mail and Thames Water.
OTM posted a turnover of 14m last year, and set itself a target of 17m for 2006.
