The Women's Environmental Network has won an appeal against a "substantially flawed" ruling by the Advertising Standards Authority (ASA).
The ASA originally upheld complaints by the disposable nappy industry about a Women's Environmental Network leaflet promoting cloth nappies.
Several thousand copies of the leaflet, which mentioned the environmental and financial costs of disposable nappies, were distributed at the start of 2002.
The Absorbent Hygiene Products Manufacturers Association, which represents disposable nappy manufacturers including Procter & Gamble and Kimberly Clarke, complained in April 2002 - a month after the leaflet went out of print.
The original ruling required the Women's Environmental Network to stop making the claims, rendering an entire batch of newly printed leaflets useless.
Liz Sutton, press and information co-ordinator, said: "The complaint undermined the real nappy campaign and cost us valuable time and resources.
"We are working on a new leaflet and are pleased that parents can make an informed choice again."