Linezolid is an antimicrobial drug which has good activity against clinically important gram-positive methicillin and vancomycin resistant microorganisms. However, linezolid is a lifesaving medicine for resistant infections, it can be responsible for severe drug interactions. Linezolid is a nonselective, weak, reversible inhibitor of monoamine oxidase A and B. That is why it can lead to increase activity of concomitant administrated monoamine oxidase inhibitors, serotonergic and adrenergic agents. This study is a one-month retrospective chart review of inpatients at a university hospital. All charts in a 1368 bed university hospital were reviewed via electronic records. Charts, which include linezolid have evaluated by clinical pharmacists and were assessed for prevalence and severity of potential drug-drug interactions using the Up- ToDate drug reference database. Fifty-four patients included in this study. Total number of interactions with linezolid was 86, which was 28.2 percent of all interactions. Eight of these interactions were in X category (avoid combination), 59 were in D category (consider therapy modification) and 19 were in C category (monitor therapy). There wasn’t any interaction classified as category B (no action needed). In our study, it was predicted that serotonergic toxicity and hypertension may develop in many patients due to concurrent administration of linezolid with serotonergic and/or adrenergic drugs. If the coadministration of these drugs is unavoidable, physicians should be alert to the symptoms and management of serotonergic toxicity and hypertension. The number of patients and its retrospective nature were limiting factors of our study. More comprehensive prospective studies are needed.