Italian Justice Minister Andrea Orlando received bullets and a threatening letter written in Arabic in the post on Thursday, a ministry spokeswoman said.
The letter and the two bullets for a Kalashnikov have been sent for analysis along with the envelope they arrived in, which was addressed to the minister and stencilled in English.
Neither Orlando nor the ministry had received threats of this kind in the past, the spokeswoman said.
Sending bullets by post is a way that Italy's organised crime groups have traditionally threatened their enemies.