In a placebo-controlled, randomized, modified double-blind study we investigated the effects of body needle acupuncture (n = 10) in 43 patients with minor depression (ICD 10 F32.0, F32.1) and 13 patients with generalized anxiety disorders (ICD10 F41.1). The severity of the disease was assessed by the Clinical Global Impression Scale (CGI). Treatment response was defined as a significant improvement in CGI. An intent-to-treat analysis was performed to compare treatment responses between verum- and placebo acupuncture. After completing an total of 10 acupuncture sessions the verum acupuncture group (n = 28) showed a significantly larger clinical improvement compared to the placebo group (Mann-Whitney test, p < 0.05). There were significantly more responders in the verum-compared to the placebo group (60.7% vs. 21.4%; chi-square test, p < 0.01). In contrast, no differences in the response rates were evident just after 5 acupuncture sessions. A multivariate analysis with the independent factor acupuncture (verum vs. placebo) and the results of the results of the additional rating scales (total score of HAMA, HAMD, Bf-S, BL) as dependent variables (ANOVA, 1:54 D.F.) revealed a clear trend towards lower HAMA scores in the verum group after completing 10 acupunctures (F3.29, p = 0.075). This corresponds well to the high response rate of 85.7% in patients with generalized anxiety disorders, in whom verum acupuncture was applied. Our results indicate that needle acupuncture (Du.20, Ex.6, He.7, Pe.6, Bl.62) leads to a significant clinical improvement as well as to a remarkable reduction in anxiety symptoms in patients with minor depression or with generalized anxiety disorders. The total sum of acupuncture sessions and the specific location of acupuncture needle insertions might be important factors for bringing about therapeutic success.