Marketers reporting their job is secure or very secure fell to 54% from 86% in September 2011, according to a poll of 500 conducted by marketing recruitment specialists EMR.
A fifth (20%) feel very insecure, up from just 2% in September.
The gloomy picture painted follows the recent downgrading of forecasted economic growth for 2012 by the Bank of England. Last week, Chancellor George Osborne warned the worsening Eurozone crisis is killing any chance of UK recovery.
Despite the increase in insecurity, those feeling secure still outnumber anxious marketers, the report found.
The largest block of respondents were those feeling secure, 44% with 54% feeling secure or very secure overall.