Abstract: This invention provides compounds of the formula: useful in the inhibition or modulation of serine palmitoyl transferase and their use in methods of treatment or amelioration of type 2 diabetes, type 1 diabetes, insulin resistance, the effects of obesity, metabolic syndrome (sometimes referred to as Syndrome X), impaired glucose tolerance, Cushing's disease, cardiovascular disease, prothrombotic conditions, myocardial infarction, hypertension, congestive heart failure, cardiomyopathy, atherosclerosis, dyslipidemia, sepsis, liver damage, retinal degenerative disorders, cachexia, emphysema, hepatitis C infections, HIV infections and inflammatory disorders and useful in methods for raising HDL plasma levels in a mammal. The compounds of this invention can also be used to prevent damage or loss of pancreatic islet beta cells (such as in the case of pancreatic beta cell apoptosis, including those related to insulin-dependent diabetes mellitus).