OBJECTIVES: The study examined antidepressant utilization patterns and expenditures in older adults in United States (US). METHODS: The study involved analysis of household and prescription files of the 2009 Medical Expenditure Panel Survey (MEPS) data. The study sample included all older adults (>= 50 years) with depression. The analysis focused on antidepressant classes, namely selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs), serotonin-norepinephrine reuptake inhibitors (SNRIs), Monoamine Oxidase Inhibitors (MAO), phenylpiperazine and tetracyclics. Descriptive weighted analysis was performed to examine antidepressant use patterns and prescription expenditures in community dwelling depressed older adults. RESULTS: According to the 2009 MEPS, 11.36 million older adults were diagnosed with depression for an overall prevalence of 11.50% (95% CI, 12.34- 47.50). Most older adults with depression were 50-64 years of age (66.79%), female (67.25%), and white (89.85%). Antidepressants were used by 78.61% (95% CI, 75.79- 81.43) of older adults with depression. The most prescribed class of antidepressants was SSRIs (54.86%), followed by SNRIs (18.49%), phenylpiperazine (7.92%), TCAs (6.96%) and tetracyclics (3.19%). Total antidepressant prescription expenditures were $9.5 billion (95% CI, 8.3-10.7 billion). High expenditures were found for SNRI ($4.3 billion, or 44.62% of antidepressant expenditures), followed by SSRI ($3.5 billion, or 37.60%)), TCA ($172 million, or 1.8%), and phenylpiperazine ($131 million, or 1.37%). The average prescription price was also highest for SNRI ($181.56), followed by SSRI ($49.22), tetracyclic ($28.17), TCA ($19.13), and phenylpiperazine ($13.64).  CONCLUSIONS: Depression is highly prevalent among older adults. Over three-fourths of older adults with depression use antidepressants for annual expenditure of nearly $10 billion, mostly for SNRIs and SSRIs.