Centurions Chris Dent and Alex Gidman put on 267 for the third wicket as Gloucestershire reached 348 for three on the opening day of their LV= County Championship Division Two game against bottom-of-the-table Kent at Cheltenham.
Gidman joined Dent in the middle after young seamer Calum Haggett had accounted for Michael Klinger and Dan Housego to leave Gloucestershire on 74 for two in the 19th over.
Dent reached his hundred from 205 deliveries and advanced to a career-best 153, with 17 fours and two sixes in a 270-ball innings, before Haggett had him caught behind.
Gidman, who survived difficult catching chances on 38 and 58, brought up his third championship century of the year from 185 balls and moved on to 145 not out at stumps, having struck 19 fours and a six.
After winning the toss, home skipper Klinger helped Dent get the innings off to a brisk start with a flurry of boundaries off South Africa star Vernon Philander and Charlie Shreck.
Haggett made the breakthrough for Kent in his second over from the College Lawn End; Klinger chased a wide delivery and only succeeded in edging it to Darren Stevens at second slip to depart for 20.
Haggett, who was released by Somerset without making a first-class appearance, struck again in his fifth over when Housego, on 13, got an inside edge onto his stumps.
Tight spells from Philander and Stevens slowed the scoring rate and an evenly balanced morning session ended with Gloucestershire on 98 for two from 31 overs.
It was a different story thereafter, though, as Dent and Gidman took advantage of the short boundaries square of the wicket and a quick outfield to lead Gloucestershire into a strong position.
Gidman enjoyed a slice of luck on 38 when Brendan Nash could not grasp a head-high chance at extra-cover off Stevens. His second reprieve came on 58 when Stevens, at backward point, failed to hold a diving catch off Philander.
Dent also offered a chance on his way to three figures. The left-handed opener flicked the third ball after tea from Charlie Shreck down the leg side, but wicketkeeper Geraint Jones missed a one-handed opportunity.
Soon after, Dent swept James Tredwell's off-spin for a single to bring up his third first-class hundred and second at Cheltenham, having scored a ton against Surrey at the ground two years ago.
Gidman reached his ton eight overs later with a single to square-leg off Tredwell; the 32-year-old is enjoying an excellent season having given up the captaincy at the end of last summer.
Dent and Gidman accelerated the scoring rate in the closing hour's play and no bowler suffered more than Tredwell, who is still searching for his first championship wicket of the summer. Dent struck him for two straight sixes and Gidman also hit a maximum over midwicket as the tweaker ended the day with 0-83 from 19 overs.
Kent finally had a third wicket to celebrate when Haggett struck with four overs of the day remaining, Dent flashing at a ball outside off stump and nicking a catch to Jones.