When do you use the passato prossimo and when the imperfetto?
The passato prossimo reports a completed event; the imperfetto describes the situation around it. If the story moves forward, use the passato prossimo. If you are describing how things were, what used to happen, or what was going on when something interrupted, use the imperfetto.
Events against background
The passato prossimo carries the plot and the imperfetto paints the scene. An Italian narrative alternates constantly between the two, and using only one produces text that is grammatical sentence by sentence and wrong as a whole.
Pioveva quando sono uscito.
It was raining when I went out.
Leggevo quando ha squillato il telefono.
I was reading when the phone rang.
Sono andato al mercato e ho comprato il pane.
I went to the market and bought bread.
Habits and descriptions
Repeated past actions take the imperfetto, matching English used to. Descriptions of age, weather, appearance and states of mind take it as well, because they describe rather than report.
Da bambino giocavo a calcio.
As a child I used to play football.
Faceva freddo e avevo paura.
It was cold and I was afraid.
Aveva vent'anni.
He was twenty.
Verbs that shift meaning
As in Spanish and French, a few verbs translate differently in the two tenses because the perfect marks the moment a state began rather than the state itself.
Sapevo / Ho saputo
I knew / I found out
Conoscevo / Ho conosciuto
I knew (someone) / I met
Volevo / Ho voluto
I wanted / I decided to
Common mistakes
Ieri leggevo per due ore.
Ieri ho letto per due ore.
A stated, finished duration is a completed event, so the passato prossimo.
Da bambino sono andato al mare ogni estate.
Da bambino andavo al mare ogni estate.
Ogni estate marks a habit, which takes the imperfetto.
Ho conosciuto mia moglie nel 2010 — meaning I already knew her.
Conoscevo mia moglie nel 2010.
The perfect of conoscere means met; the imperfetto means already knew.
Frequently asked questions
What about the passato remoto?
It is a third past tense, standard in written narrative and still spoken in parts of southern Italy. Northern speakers use the passato prossimo where southerners might use the remoto, so exposure varies by region — recognise it for reading, and you rarely need to produce it.
Is there a quick test?
Ask whether you are saying what happened or what things were like. A stated duration, a start or an end usually signals the passato prossimo; habit, description and ongoing background signal the imperfetto.
Can both appear in one sentence?
Yes, and that is the normal pattern for any sentence containing an interruption — background in the imperfetto, interrupting event in the passato prossimo.