Depression (Major Depressive Disorder) is a serious medical illness that affects how we think, how we act and our mood in a negative way. Depression is dangerous because it can affect anyone from teenagers to adults and elderly and it can haunt the patient with lingering thought of death or suicide. Fortunately, this illness is treatable. Antidepressant medications are recommended in every step of depression treatment, from acute phase to continuation phase to maintenance phase. At first, TCAs and MAOIs were widely used but after a while they become second-line treatments due to their complicated adverse effects. The secondary generation of antidepressants including SSRIs, SNRIs, atypical antidepressants are more tolerable, safer and cost-effective. Therefore, nowadays, the most commonly prescribed antidepressants are SSRIs, SNRIs, bupropion and mirtazapine. The combination with other therapies such as cognitive behavioural therapy, psychotherapy, electroconvulsive therapy is needed to improve the outcome of depressed patients and to prevent relapse.