It depends on the type of kissing. There is no risk from closed-mouth kissing.

There are extremely rare cases of HIV being transmitted via deep “French” kissing but in each case, infected blood was exchanged due to bleeding gums or sores in the mouth. Because of this remote risk, it is recommended that individuals who are HIV-infected avoid deep, open-mouth “French” kissing with a non-infected partner, as there is a potential risk of transferring infected blood. Summary:

• There is no risk of transmission closed-mouth kissing.
• There is a remote risk from deep, open-mouth kissing if there are sores or bleeding gums and blood is exchanged. Therefore, persons living with HIV should avoid this behavior with a non-infected partner.