Mitigation of penalty is the lessening, or reducing, of the penalty.

After the prosecutor has provided the appropriate details to the court, the defendant (or their lawyer) then presents any facts or other relevant information in mitigation of penalty and on what might be the most appropriate penalty.

They may also present any relevant evidence such as character evidence or expert reports such as a psychological or psychiatric report. This maybe in a writing or spoken to the court.

Prior to sentencing the court may also order a pre-sentence report. This maybe a report from an expert, such as a psychologist or psychiatrist or a probation officer from the Department of Correctional Services (DCS). This will often cover any issues that may have lead to the offending behaviour such as alcoholism, drug abuse, or mental health concerns, and it will also cover the appropriateness of any of the rehabilitation or intervention programmes. It will also cover general information about the defendants background, family life, education and work history. When a pre-sentence report has been requested, the court usually adjourns the case for four to six weeks for the report to be prepared.

Witnesses may be called to give evidence of the defendant's good character or to explain the circumstances that led to the offence. The defence may present to the court references of the defendant's character, but only with the consent of the prosecutor, unless the referee is in court giving evidence.

The defendant may give evidence in the witness box about the reasons for the offence or any mitigating circumstances. Medical, psychological or psychiatric evidence may also be presented to explain their background and why they may have acted in the way they did.

The court then imposes penalty, see Penalties. The reasons for the sentence should be stated and its legal effect explained to the defendant [Sentencing Act 2017 (SA) s 19].