In June 2007 he signed for Chesterfield on a 3-year contract. He finished the 2007/08 season as Chesterfield's top scorer, with 25 goals in all competitions. This tally made him 3rd top scorer in League Two, with 23 goals in the league, 6 behind Aaron McLean of Peterborough United. That season he also became the fastest post-war Chesterfield player to 20 goals in a season, getting his 20th (and 100th career goal) live on TV against Hereford United. He finished the season third in England on goal to game ratio, behind Cristiano Ronaldo and Fernando Torres. Lester scored his 100th League career goal in the 2–1 win over Exeter City on 28 January 2009. He also set a club record in becoming the first striker at the club to score 20 goals in consecutive seasons for 82 years. Despite scoring fewer goals than in his first season at Chesterfield, he finished the 2008/9 term as joint-top scorer for League Two, with 20 League goals.