The present invention relates to a Lactuca sativa seed designated 41-342 RZ, which exhibits a combination of traits including resistance to downy mildew (Bremia lactucae) races Bl:1 to Bl:12, Bl:17, Bl:18, Bl:22, Bl:24, Bl:25, Bl:28-Bl:30, resistance to currant-lettuce aphid (Nasonovia ribisnigri) biotype Nr:0, resistance to Lettuce Mosaic Virus (LMV) race LMV:1, as well as very thick mature leaves and a small head size. The present invention also relates to a Lactuca sativa plant produced by growing the 41-342 RZ seed. The invention further relates to methods for producing the lettuce cultivar, represented by lettuce variety 41-342 RZ.
