Which is the correct usage: "With regard to/with regards to" or "In regard to/in regards to?"
The correct usage is the singular with (or in or having) regard to.
He made enquiries with regard to Beth.
Some people confuse the singular with the plural because there's a similar usage of the word regard in the plural form that is used to introduce a topic.
As regards content, the programme will cover important current issues.
Source: ODE