quick tax (cg) question

Just a quick tax question:

If we incurred a tax loss by selling shares at a loss, does this loss offset any gains subsequently?

eg sold xxx shares for a monumental loss this FY (say $150k loss)
then bought yyy shares and sold for a profit (say $20k profit), do we still have to pay CG on the first 50% of the $20k, or can we offset the monumental loss against the modest CG?

sorry if it is a stupid question, but it reflects my lack of working knowledge.

Cheers
VT