In New Mexico, State District Judge Theresa Baca found that Nader does not qualify as an independent under state law because he is running in other states as the nominee for minor parties.
Baca's decision came hours after another judge - who had issued a similar ruling last Friday- recused herself from the case after complaints about her $1,000 donation to Democrat John Kerry's campaign.
The state Democratic Party had challenged Nader's candidacy, as Democrats have done in other states. New Mexico election law defines an independent as someone not affiliated with a political party.
Nader's campaign said it would appeal to New Mexico's Supreme Court.
An appeal also was planned in Arkansas, where Pulaski County Circuit Judge Timothy Fox ruled that more than 1,200 people who signed Nader's petitions failed to declare him as their candidate, and ordered his name removed from the ballot. Fox said no specific party was listed as canvassers went about collecting signatures.
"We think this is a mistaken decision and we'll appeal it to ensure that voters of Arkansas have more choices and not less," said Nader spokesman Kevin Zeese.
State Democrats challenged the petitions, saying more than 360 signatures could not be matched in a state database.
In Maryland, Nader qualified for the ballot Monday after the state's highest court ordered elections officials to accept 542 previously rejected petition signatures.
Democrats nationwide have challenged Nader's ballot petitions, fearing his candidacy will siphon votes from Kerry, especially in battleground states like New Mexico. Many Democrats blame Nader's presidential candidacy in 2000 for Democrat Al Gore's loss.
Nader is on the ballot in 37 states and in litigation in seven of those. The campaign also is suing for ballot access in seven other states.