Grimsby's Nick Fenton scored against his former club to earn his current side a point at Meadow Lane.
Grimsby missed three clear-cut chances, Danny North's shot cleared off the line, Peter Till having a shot saved and Kevin Pilkington denying North.
Ryan Jarvis missed a golden chance for County before Richard Butcher fired in after a defensive ricochet.
But Grimsby immediately struck back to claim a point, Fenton slamming in from Danny Boshell's pass.
Notts County: Pilkington, Canoville, Edwards, Tann, Hunt, Gibb (Weston 74), Silk, Strachan, Butcher, Lee (Weir-Daley 81), Jarvis (Dudfield 88).
Subs Not Used: McCann, Smith.
Goals: Butcher 59.
Grimsby: Barnes, Bennett, Fenton, Hird, Clarke, Atkinson, Hunt, Boshell, Hegarty, Till, North (Jones 90).
Subs Not Used: Montgomery, Whittle, Bore, Taylor.
Goals: Fenton 61.
Ref: Roger East (Wiltshire).