Sarcina are gram-positive anaerobic bacteria found to be associated with delayed gastric emptying and gastric outlet obstruction. We describe two cases of Sarcina co-existing with Helicobacter pylori organisms in pediatric siblings presenting within four months of each other with pyloric obstruction secondary to severe gastritis/duodenitis. The co-existence of Sarcina and Helicobacter pylori has not, to our knowledge, been previously reported. Its characteristic tetrad packeted morphology permits Sarcina to be readily identified on routine sections. Detection of these organisms in gastric biopsies should prompt consideration of gastric outlet obstruction and/or delayed gastric emptying as a possible etiologic factor.