I've used geom_point and geom_hline in ggplot2 and have gotten satisfactory legends for both. However, I have one black line and one blue line in the figure but in the legend they are both black - how can I correct this in the legend to be the right colors? mcgc <- ggplot(sam, aes(x = m,y = ad, colour = X)) + geom_point(size = 0.75) + scale_colour_gradient2(high="red", mid="green", limits=c(0,1), guide = "colourbar") + geom_hline(aes(yintercept = mad, linetype "mad"), colour = "blue", size=0.75, show_guide = TRUE) + geom_hline(aes(yintercept = mmad, linetype "mmad"), colour = "black", size=0.75, show_guide = TRUE) + facet_wrap(~ Plan, scales = "free", ncol = 4) + scale_linetype_manual(name = "Plan of Health Care", values = c("mad" = 1, "mmad" = 1),guide = "legend") I'm sure I've over written something here... just not sure where (am new to ggplot) Data: Plan ad X m mad mmad 1 1 95 0.323000 0.400303 0.12 1 2 275 0.341818 0.400303 0.12 1 3 2 0.618000 0.400303 0.12 1 4 75 0.320000 0.400303 0.12 1 5 13 0.399000 0.400303 0.12 1 6 20 0.400000 0.400303 0.12 2 1 219 0.393000 0.353350 0.45 2 2 50 0.060000 0.353350 0.45 2 3 213 0.390000 0.353350 0.45 2 4 204 0.496100 0.353350 0.45 2 5 19 0.393000 0.353350 0.45 2 6 201 0.388000 0.353350 0.45 Plan goes up to 40, but I've only included a snippet of data here...