In humans, the type I interferon (IFN) family consists of 13 IFN‐α subtypes, IFN‐β and IFN‐o the newly discovered IFN‐like family consists of IFN‐λ1, ‐λ2 and ‐λ3. We have investigated the expression of type I and λ IFN genes following virus infections or Toll‐like receptor (TLR) triggering in monocyte‐derived DC (MDDC) and plasmacytoid DC (pDC). We found thatall IFN‐α, ‐β, ‐o and ‐λ subtypes are expressed in influenza‐virus‐infected MDDC or pDC. Conversely, differential type I IFN gene transcription was induced in MDDC and pDC stimulated by specific TLR agonists. TLR‐9 stimulation by CpG DNA induced the expression of all IFN‐α, ‐β, ‐o and ‐λ subtypes in pDC, whereas TLR‐4 stimulation by LPS, or TLR‐3 stimulation bypoly I:C, induced only IFN‐β and IFN‐λ gene expression in MDDC. The expression pattern of IFN regulatory factor (IRF)‐5 and IRF‐7 in MDDC and pDC was also determined. IRF‐5 was constitutively expressed in the two DC subsets whereas IRF‐7 was constitutive in pDC but its expression was induced along MDDC maturation. Overall, our data indicate that the coordinated expression of IFN‐λ with IFN‐β would be of crucial importance for the maturation of DC.