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The paper reviews t h e s t a t e of t h e a r t of primary laboratory atomic frequency standards. Emphasis w i l l be put on t h e new techniques being used i n t h e f i e l d such a s i o n trapping, l a s e r cooling and o p t i c a l pumping, t o implement more a c c u r a t e primary o p t i c a l o r microwave frequency standards. Progress made a t NRC on t h e s u b j e c t w i l l be outlined.F i n a l l y t h e c e n t r a l r o l e of time a s a base q u a n t i t y of t h e i n t e r n a t i o n a l system of u n i t s w i l l be discussed. Summary Atomic frequency standards of t h e c l a s s i c a l t y p e s u c h a s o p t i c a l l y pumped r u b i d i u m c e l l standards, hydrogen masers and cesium beam frequency standards have improved over t h e l a s t few decades and extensive developments have made them r a t h e r s t a b l e frequency sources and i n t h e case of cesium, a very a c c u r a t e primary standard. However, a t -t h i s time i t appears t h a t f u r t h e r development of these d e v i c e s by simply improving e l e c t r o n i c s and mechanical design, although bound t o improve t h e i r performance s l i g h t l y , w i l l not i n c r e a s e t h e i r accuracy or s t a b i l i t y by orders of magnitude. Consequently during t h e l a s t s e v e r a l years other approaches have been looked a t and appear t o be extremely promising. Among them trapping and l a s e r c o o l i n g of atoms of i o n s t o c r e a t e e i t h e r a microwave or an o p t i c a l frequency standard shows a l o t of promise.A proposed o p t i c a l frequency standard using a single-laser-cooled i o n is on top of t h e l i s t , but c r e a t e s new challenges because, f o r