Will Gidman added a half-century to his five-wicket haul and Geraint Jones rolled back the years with a brutal 93 for Gloucestershire, but it was Leicestershire who marginally held the edge after day two at Grace Road.
Gidman followed up his 5-56 yesterday with an unbeaten 52, while former England wicketkeeper Jones fell just short of a blistering century to lead their side's reply to Leicestershire's 269 all out.
However, their efforts were not enough to earn Gloucestershire a first-innings lead as a late collapse saw them dismissed for 260, left and right-arm seam duo Rob Taylor and Nathan Buck taking 5-55 and 4-81 respectively.
Leicestershire then reached 12 without loss in their second innings, for an overall lead of 21, before bad light and then rain brought an early end to proceedings.
The home side, looking for their first LV= County Championship Division Two win of the season, made good progress during the morning session to reduce Gloucestershire to 94 for four at lunch - having started the day 12 for nought.
Chris Dent and Hamish Marshall both fell to Buck, while Taylor accounted for Alex Gidman and the dangerous Michael Klinger for 37 to leave Leicestershire firmly in the box seat at the interval.
However, Jones and Will Gidman then led a Gloucestershire fightback in the afternoon with a fifth-wicket stand worth 107.
The 37-year-old Jones, who recently joined on loan from Kent, led the charge as he struck 13 fours and three sixes off 75 balls before his onslaught was brought to an end by Jigar Naik, trapped lbw.
While Jones and Will Gidman were together Gloucestershire looked capable of claiming a sizeable lead, but once that stand was broken the end was not long in coming for the visitors as they lost their last six wickets for just 65 runs.
Only Will Gidman stood firm, finishing unbeaten on 52 off 123 balls with seven fours, as Taylor - claiming his second five-wicket haul in first-class cricket - and Buck ran through the tail.
Greg Smith, who was out for a golden duck in the first innings, and Angus Robson then saw the hosts through to the close, finishing on 10 and two respectively.