The EIS called for a ballot on industrial action unless better resources are provided for the National exams, which replaced Standard Grades. The union's AGM has already approved strike ballots on issues including pay, pensions and workload.
Teachers spoke of colleagues in floods of tears, unable to cope with the introduction of the new National qualifications, which replaced Standard Grades this summer.
The meeting heard some pupils were taking more than 40 assessments, with some being taken to their GP as they couldn't cope.
Andy Harvey, from the South Lanarkshire local association, told the meeting on Friday that bureaucracy was "sucking the life" out of schools and called on the Scottish Qualifications Authority (SQA) to reduce the number of internal assessments.
Brian McGovern, of the Renfrewshire local association said: "The time for talking is over."