Mr Collymore had stepped away from the firm's helm for 9 months too seek treatment for an undisclosed illness
Safaricom chief executive Bob Collymore appeared Monday morning before parliament's ICT committee, marking his first public event after a long absence.
The National Assembly team is looking into telcos dominance in the Kenyan market that has seen top managers of telecommunications firms appear before legislators amid a push by competitors to have Safaricom declared dominant.
Mr Collymore, who had stepped away from the firm's helm for 9 months to seek treatment for an undisclosed illness, thanked well wishers for their support
"I'm back. Thanks to everyone who supported me over the past 9 months especially the clinical team at @UCLH, my superb @SafaricomPLC team and of course my wife Wambui Kamiru," he tweeted on Monday.
The Safaricom boss informed investors in May that he would be returning from his extended medical leave as soon as doctors in London cleared him to travel.