The present application provides pyrrolo(oxo)isoquinolines as modulators of serotonin receptors, pharmaceutical compositions containing such modulators and methods for treating various diseases, conditions and disorders associated with modulation of serotonin receptors such as, for example: metabolic diseases, which includes but is not limited to obesity, diabetes, diabetic complications, atherosclerosis, impared glucose tolerance and dyslipidemia; central nervous system diseases which includes but is not limited to, anxiety, depression, obsessive compulsive disorder, panic disorder, psychosis, schizophrenia, sleep disorder, sexual disorder and social phobias; cephalic pain; migraine; and gastrointestinal disorders using such compounds and compositions.