NHS Grampian has been told it must give staff enough time to complete mandatory hand hygiene courses - after inspectors found just 9% of staff on one hospital ward had completed them.
It follows an unannounced inspection at Aberdeen's Woodend Hospital in May.
Healthcare Inspectorate Scotland has issued five requirements and one recommendation.
NHS Grampian said it had agreed an action plan and had already seen an improvement in its training rates.
The inspectors found that while some wards had good compliance levels, they were poor in three others.
They said the majority of patient equipment was clean and said staff had a good knowledge about the safe management of blood and body fluid spillages.
However, the inspectors said staff must complete mandatory Healthcare Associated Infection (HAI) training and that detailed action plans must be put in place.
Action plan agreed
They also said staff and volunteers should comply with hand hygiene and the use of personal protective equipment for all patients, including those in isolation.
An NHS Grampian spokeswoman said: "There is much to be positive about in this report. It is clear staff have a good relationship with the infection prevention and control team.
"They feel able to challenge those colleagues not complying with standard infection control measures. Furthermore, all the patients spoken to by the inspectors felt the standard of cleanliness on their ward was good and any equipment used was clean.
"However, there are areas where we can do better.
"A full action plan has already been agreed to deal with these issues utilising a multi-disciplinary team approach to aid improvements.
She added: "We are working to ensure staff have the protected time away from their busy workplace environment to undertake training.
"We have already seen improvements in the compliance with HAI training and, in partnership with supporting services, in all other areas of improvement identified within the report."