Four Virginia Democrats considered likely contenders for Harry F. Byrd Jr.'s Senate seat met yesterday but reached no conclusion as to who should be the nominee, according to informed sources.

The four agreed to meet again and to say nothing about what happpened at yesterday's session. The meeting was originally expected to be held in a Fredericksburg hotel but was moved after news accounts appeared.

Those attending the meeting were former Virginia attorney general Andrew P. Miller of Alexandria, state Senate Majority Leader Hunter B. Andrews of Hampton, state Democratic Chairman Owen Pickett of Virginia Beach and Alexandria lawyer William Thomas, a former state party chairman and influential lobbyist close to Gov.-elect Charles S. Robb.

"We had a nice meeting," said Andrews, who declined to provide any detail. He said that the meeting was not held in Fredericksburg, but would not disclose its location.

Originally designed as a meeting between Miller and Andrews, the gathering was later expanded to include the other two.

Some politicians have questioned whether any decision made at the meeting would be binding, noting that there are other possible candidates, including Fairfax Commonwealth's Attorney Robert F. Horan Jr.

Republicans have moved more quickly than Democrats in trimming the field of candidates since Byrd announced Nov. 30 he would step down at the end of his term.

Last month Republican Rep. Paul S. Trible of Newport News appeared to be his party's front-runner for the nomination.