diff --git a/NEWS.md b/NEWS.md
index c81ec11d..48fda94a 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -12,6 +12,14 @@
   manifest created for an renv project references the `renv.lock` in the
   `manifest.json`. (#926)
 
+* Use the environment variable `RSCONNECT_PACKRAT` to analyze dependencies
+  using packrat, as was done prior to rsconnect-1.0.0. Use of the
+  `rsconnect.packrat` option is discouraged, as it is not effective when using
+  push-button deployment in the RStudio IDE. (#935)
+
+* The `renv.lock` is ignored when the `RSCONNECT_PACKRAT` environment variable
+  or the `rsconnect.packrat` option is set. (#936)
+
 # rsconnect 1.0.1
 
 * `deployDoc()` includes `.Rprofile`, `requirements.txt` and `renv.lock` when
diff --git a/R/bundlePackage.R b/R/bundlePackage.R
index cad17ed4..54fa0a1f 100644
--- a/R/bundlePackage.R
+++ b/R/bundlePackage.R
@@ -29,12 +29,26 @@ bundlePackages <- function(bundleDir,
   packages_list
 }
 
+usePackrat <- function() {
+  # Use RSCONNECT_PACKRAT when it has any value; fall-back to rsconnect.packrat when the environment
+  # variable is unset.
+  env_value <- Sys.getenv("RSCONNECT_PACKRAT", unset = NA)
+  if (is.na(env_value)) {
+    return(isTRUE(getOption("rsconnect.packrat", FALSE)))
+  }
+  
+  return(truthy(env_value))
+}
+
 computePackageDependencies <- function(bundleDir,
                                        extraPackages = character(),
                                        quiet = FALSE,
                                        verbose = FALSE) {
 
-  if (file.exists(renvLockFile(bundleDir))) {
+  if (usePackrat()) {
+    taskStart(quiet, "Capturing R dependencies with packrat")
+    deps <- snapshotPackratDependencies(bundleDir, extraPackages, verbose = verbose)
+  } else if (file.exists(renvLockFile(bundleDir))) {
     # This ignores extraPackages; if you're using a lockfile it's your
     # responsibility to install any other packages you need
     taskStart(quiet, "Capturing R dependencies from renv.lock")
@@ -42,13 +56,10 @@ computePackageDependencies <- function(bundleDir,
     # Once we've captured the deps, we can remove the renv directory
     # from the bundle (retaining the renv.lock).
     removeRenv(bundleDir, lockfile = FALSE)
-  } else if (isFALSE(getOption("rsconnect.packrat", FALSE))) {
+  } else {
     taskStart(quiet, "Capturing R dependencies with renv")
     # TODO: give user option to choose between implicit and explicit
     deps <- snapshotRenvDependencies(bundleDir, extraPackages, verbose = verbose)
-  } else {
-    taskStart(quiet, "Capturing R dependencies with packrat")
-    deps <- snapshotPackratDependencies(bundleDir, extraPackages, verbose = verbose)
   }
   taskComplete(quiet, "Found {nrow(deps)} dependenc{?y/ies}")
 
diff --git a/R/utils.R b/R/utils.R
index 56b97f02..261a8cfe 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -161,3 +161,16 @@ toJSON <- function(x, ...) {
     ...
   )
 }
+
+truthy <- function(value, default = FALSE) {
+  if (length(value) == 0)
+    default
+  else if (is.character(value))
+    value %in% c("TRUE", "True", "true", "T", "1")
+  else if (is.symbol(value))
+    as.character(value) %in% c("TRUE", "True", "true", "T", "1")
+  else if (is.na(value))
+    default
+  else
+    as.logical(value)
+}