We have the Safety Data Sheets for all of our hazardous substances; do we still need to carry out COSHH risk assessments?

YES. A good safety data sheet (SDS) does not substitute for carrying out and recording a COSHH risk assessment. Gathering SDSs is only the first stage in the assessment process. The SDS will provide information on the hazardous properties of the substances you are using, any health effects associated with its use, how likely it is to get into the air or onto the skin, and what risk reduction measures you should use to control exposure to an acceptable level. However, it will not be specific to your workplace and cannot take into account the particular environment you work in. Working with substances hazardous to health provides more information.