A Care Quality Commission (CQC) inspection of Firtree House Nursing Home, in Banstead, found staff leaving medicines unattended.
Its report also said that sharps bins were found to be overflowing.
However, staff were seen to carry out appropriate checks before they administered medicines and staffing had improved since the last inspection.
The report, following an inspection in July, also said the home had improved in respect of telling the CQC when people had died there.
This was compared to the last CQC inspection in February.
The report said: "People were at risk because medicines were not managed safely.
"Staff were seen to carry out appropriate checks before they administered medicines, however we saw staff leaving medicines unattended when preparing them.
"The system for safe storage and disposal of medicines was not effective, with overflowing sharps bins and large amounts of waste medicines in the locked medicines room."
Residents at a care home in Surrey were deemed "at risk" after inspectors found that medicines were not managed safely.