A ninth goal of the campaign from Sligo’s attacking midfielder Kieran Sadlier, who netted the game’s only goal after 13 minutes, consigned bottom of the table Longford to their 21st loss of a dire Premier Division campaign.
Sligo, beaten at home just twice all season, came into this game on the back of a superb 3-0 away win over champions Dundalk.
Struggling Longford had won only twice all year ahead of their trip to The Showgrounds.
Sligo took a 13th minute lead when Kieran Sadlier scored from an acute angle, Tobi Adebayo-Rowling providing the through ball, but Longford goalkeeper Ryan Coulter should have done better at his near post.
Longford, who trailed 1-0 at half-time, failed to seriously Sligo goalkeeper Ciaran Nugent in the opening period.
A flat second-half failed to produce anything of note as Sligo held on for their fifth successive clean sheet.
Nugent; Adebayo-Rowling, Leahy, Peers, Boylan; McCann, Roddan, Sadlier (Kearns 67), Keohane; Roberts, Cretaro.
Coulter; Mulhall, Haverty (Gorman 63), Flynn, Powell; Cowan, McGlynn, Gannon (Dillon 83), O’Connor, Simon (D’sane 65); O’Sullivan