Germany continues to be iodine deficient despite considerable improvement in the past years. To assess the current prevalence of diffuse and/or nodular thyroid disorders, a cross-sectional observational study in a nonrandom sample of the working population was carried out throughout Germany in 2001 and 2002. A total of 96,278 employees 18-65 years of age from 214 companies or other private or public institutions voluntarily underwent ultrasonographic examinations by 230 experienced investigators. To compare the prevalence of different abnormal findings in relation to age and gender, descriptive statistics and the Kruskal-Wallis test were used. Data from volunteers with previous thyroid treatment (13.0% of total sample) were not included in the analysis. Abnormal findings (goiter and/or nodules > 0.5 cm) were observed in 33.1% (men, 32.0%; women, 34.2%) of the examined patient population, an enlarged thyroid without nodules in 9.7% (men, 11.9%; women, 7.6%), nodules only without enlargement of the thyroid in 14.3% (men, 11.5%; women, 17.0%), and nodular goiter in 9.1% (men, 8.6%; women, 9.6%). Nodules (with or without goiter) between 0.5 and up to 1.0 cm were found in 10.0%, and nodules above 1.0 cm in 11.9% of the population. Rates of abnormal findings increased with age in both genders. Goiter was more common in men, nodules in women. In light of these findings, the prevalence of thyroid disorders in Germany continues to be high. Although the study may slightly overestimate the prevalence, about one third of the working population is affected and remains unaware of this condition. These results emphasize the importance of effective sonographic screening to detect early thyroid abnomalities in order to initiate preventive and therapeutic measures to prevent the onset or progression of disease and its sequels.