/subito/ is the Italian for 'immediately'; /adesso/ is the Italian for 'now'; You use /subito/ when there is urgency, or even fear for something that should be done, or that you are expecting to happen; You use /adesso/ just as a plain statement about this particular moment of time (now), usually without feelings about it; To make the subject a little bit more complex, sometimes /adesso/ is used with a similar meaning of /subito/, the voice tone and the context will guide you to that meaning; /subito/ is never used as a plain statement of /now/. Examples: --- Presto, esci subito da casa, altrimenti (otherwise) perdiamo il volo (flight). --- Cosa stai facendo adesso ? (/subito/ would be just wrong here) --- Adesso ho molto da fare, non posso venire subito da te. --- Il nostro capo vuole vedere subito i risultati, ma come si fa ? --- E adesso che facciamo ? Siamo senza chiavi di casa (/subito/ would be wrong here) --- torniamo subito sulla strada, forse le abbiamo perse camminando e sono ancora sul marciapiedi (/adesso/ would not be appropriate here)

Adesso = now Subito = immediately The difference is as subtle as the English translation of the words.