diff --git a/include/PSLP/PSLP_API.h b/include/PSLP/PSLP_API.h
index 7bc2e47e..060793c5 100644
--- a/include/PSLP/PSLP_API.h
+++ b/include/PSLP/PSLP_API.h
@@ -70,6 +70,12 @@ extern "C"
         // variable bounds lbs <= x <= ubs
         double *lbs;
         double *ubs;
+
+        /* offset to be added to the objective value. (When the presolver fixes
+           variables, it adds an offset to the objective. This offset should
+           possibly be taken into account when evaluating the relative optimality gap
+           of the reduced problem.) */
+        double obj_offset;
     } PresolvedProblem;
 
     /* struct corresponding to the presolver:
diff --git a/src/core/Presolver.c b/src/core/Presolver.c
index f9a9052f..5342034d 100644
--- a/src/core/Presolver.c
+++ b/src/core/Presolver.c
@@ -536,6 +536,7 @@ void populate_presolved_problem(Presolver *presolver)
     ps_prob->rhs = constraints->rhs;
     ps_prob->lhs = constraints->lhs;
     ps_prob->c = presolver->prob->obj->c;
+    ps_prob->obj_offset = presolver->prob->obj->offset;
 
     // create bounds arrays
     ps_prob->lbs = (double *) malloc(A->n * sizeof(double));