diff --git a/NAMESPACE b/NAMESPACE
index 0a2bd9d6..bb5b032d 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -31,6 +31,7 @@ export(GetSeed)
 export(GetXYDataFromPlot)
 export(HighlightCellsOnSeuratPlot)
 export(InspectSeurat)
+export(LogNormalizeUsingAlternateAssay)
 export(MakeEnrichmentDotPlot)
 export(MergeSeuratObjs)
 export(NanoString_Housekeeping_Normalization)
diff --git a/R/Preprocessing.R b/R/Preprocessing.R
index 2b7d770d..93d5974b 100644
--- a/R/Preprocessing.R
+++ b/R/Preprocessing.R
@@ -293,4 +293,40 @@ PerformEmptyDrops <- function(seuratRawData, emptyDropNIters, fdrThreshold=0.001
 	}
 
 	stop(paste0('Unable to find matrix file in: ', dataDir, ' or ', dirWithFeatureMatrix))
+}
+
+#' @title LogNormalizeUsingAlternateAssay
+#'
+#' @param seuratObject The seurat object
+#' @param assayToNormalize The name of the assay to normalize
+#' @param assayForLibrarySize The name of the assay from which to derive library sizes. This will be added to the library size of assayToNormalize.
+#' @param scale.factor A scale factor to be applied in normalization
+#' @param maxLibrarySizeRatio This normalization relies on the assumption that the library size of the assay being normalized in negligible relative to the assayForLibrarySize. To verify this holds true, the method will error if librarySize(assayToNormalize)/librarySize(assayForLibrarySize) exceeds this value
+#' @export
+LogNormalizeUsingAlternateAssay <- function(seuratObj, assayToNormalize, assayForLibrarySize = 'RNA', scale.factor = 1e4, maxLibrarySizeRatio = 0.006) {
+	toNormalize <- Seurat::GetAssayData(seuratObj, assayToNormalize, slot = 'counts')
+	assayForLibrarySizeData <- Seurat::GetAssayData(seuratObj, assay = assayForLibrarySize, slot = 'counts')
+
+	if (any(colnames(toNormalize) != colnames(assayForLibrarySize))) {
+		stop(paste0('The assayToNormalize and assayForLibrarySize do not have the same cell names!'))
+	}
+
+	margin <- 2
+	ncells <- dim(x = toNormalize)[margin]
+
+	for (i in seq_len(length.out = ncells)) {
+		x <- toNormalize[, i]
+		librarySize <- sum(x) + sum(assayForLibrarySizeData[, i])
+
+		if ((sum(x) / librarySize) > maxLibrarySizeRatio) {
+			stop(paste0('The ratio of library sizes was above maxLibrarySizeRatio for cell: ', colnames(assayForLibrarySizeData)[i], '. was: ', (sum(x) / librarySize), ' (', sum(x), ' / ', librarySize, ')'))
+		}
+
+		xnorm <- log1p(x = x / librarySize * scale.factor)
+		toNormalize[, i] <- xnorm
+	}
+
+	seuratObj <- Seurat::SetAssayData(seuratObj, assay = assayToNormalize, slot = 'data', new.data = toNormalize)
+
+	return(seuratObj)
 }
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diff --git a/man/LogNormalizeUsingAlternateAssay.Rd b/man/LogNormalizeUsingAlternateAssay.Rd
new file mode 100644
index 00000000..87a59456
--- /dev/null
+++ b/man/LogNormalizeUsingAlternateAssay.Rd
@@ -0,0 +1,28 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/Preprocessing.R
+\name{LogNormalizeUsingAlternateAssay}
+\alias{LogNormalizeUsingAlternateAssay}
+\title{LogNormalizeUsingAlternateAssay}
+\usage{
+LogNormalizeUsingAlternateAssay(
+  seuratObj,
+  assayToNormalize,
+  assayForLibrarySize = "RNA",
+  scale.factor = 10000,
+  maxLibrarySizeRatio = 0.006
+)
+}
+\arguments{
+\item{assayToNormalize}{The name of the assay to normalize}
+
+\item{assayForLibrarySize}{The name of the assay from which to derive library sizes. This will be added to the library size of assayToNormalize.}
+
+\item{scale.factor}{A scale factor to be applied in normalization}
+
+\item{maxLibrarySizeRatio}{This normalization relies on the assumption that the library size of the assay being normalized in negligible relative to the assayForLibrarySize. To verify this holds true, the method will error if librarySize(assayToNormalize)/librarySize(assayForLibrarySize) exceeds this value}
+
+\item{seuratObject}{The seurat object}
+}
+\description{
+LogNormalizeUsingAlternateAssay
+}
diff --git a/tests/testthat/test-seurat.R b/tests/testthat/test-seurat.R
index adf89042..a6cdf07b 100644
--- a/tests/testthat/test-seurat.R
+++ b/tests/testthat/test-seurat.R
@@ -1,4 +1,4 @@
-library(DropletUtils);
+library(DropletUtils)
 
 context("scRNAseq")
 
@@ -124,4 +124,22 @@ test_that("Serat SCTransform works as expected", {
 
   expect_equal(length(rownames(seuratObjSCT@assays$SCT@scale.data)), length(rownames(seuratObjSCT@assays$SCT@counts)))
   expect_equal(ncol(seuratObjSCT), ncol(seuratObj))
+})
+
+
+test_that("LogNormalizeUsingAlternateAssay works as expected", {
+  seuratObj <- suppressWarnings(Seurat::UpdateSeuratObject(readRDS('../testdata/seuratOutput.rds')))
+
+  assayToAdd <- Seurat::GetAssayData(seuratObj, assay = 'RNA', layer = 'counts')
+  assayToAdd <- assayToAdd[1:10,]
+  assayToAdd <- assayToAdd / 50
+  rownames(assayToAdd) <- paste0('Feature', LETTERS[1:10])
+
+  seuratObj[['Norm']] <- Seurat::CreateAssayObject(assayToAdd)
+
+  seuratObj <- LogNormalizeUsingAlternateAssay(seuratObj, assayToNormalize = 'Norm', assayForLibrarySize = 'RNA')
+
+  nd <- Seurat::GetAssayData(seuratObj, assay = 'Norm', layer = 'data')
+  expect_equal(max(nd[,2]), 0.3087937)
+  expect_equal(max(nd[,100]), 0.7821186)
 })
\ No newline at end of file