The present invention relates to compounds of formula (I): and pharmaceutically acceptable salts thereof, which are useful as inhibitors of human stearoyl-CoA desaturase (SCD). The invention further relates to pharmaceutical compositions comprising these compounds and to the use of these compounds for the treatment or prevention of medical conditions in which the modulation of SCD activity is beneficial, such as cardiovascular diseases, obesity, non-insulin-dependent diabetes mellitus, hypertension, metabolic syndrome, neurological diseases, immune disorders, cancer and various skin diseases.