diff --git a/GPy/inference/optimization.py b/GPy/inference/optimization.py
index 589ec4c7..e65b862e 100644
--- a/GPy/inference/optimization.py
+++ b/GPy/inference/optimization.py
@@ -29,7 +29,7 @@ class Optimizer():
 
     """
     def __init__(self, x_init, messages=False, model=None, max_f_eval=1e4, max_iters=1e3,
-                 ftol=None, gtol=None, xtol=None):
+                 ftol=None, gtol=None, xtol=None, bfgs_factor=None):
         self.opt_name = None
         self.x_init = x_init
         self.messages = messages
@@ -39,6 +39,7 @@ class Optimizer():
         self.status = None
         self.max_f_eval = int(max_f_eval)
         self.max_iters = int(max_iters)
+        self.bfgs_factor = bfgs_factor
         self.trace = None
         self.time = "Not available"
         self.xtol = xtol
@@ -128,6 +129,8 @@ class opt_lbfgsb(Optimizer):
             print "WARNING: l-bfgs-b doesn't have an ftol arg, so I'm going to ignore it"
         if self.gtol is not None:
             opt_dict['pgtol'] = self.gtol
+        if self.bfgs_factor is not None:
+            opt_dict['factr'] = self.bfgs_factor
 
         opt_result = optimize.fmin_l_bfgs_b(f_fp, self.x_init, iprint=iprint,
                                             maxfun=self.max_iters, **opt_dict)