diff --git a/NEWS.md b/NEWS.md
index 2bc593fe..6ae61cce 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -13,6 +13,10 @@
  
 ## New features and improvements
 
+ * Conditions that are always true because they depend on fixed parameters are
+   replaced by a `TRUE` value to speed up their evaluation. This speed-up is only
+   measurable with very large and complicated parameter space.
+ 
  * The options `src` and `target` of `ablation()` (or `--src` and `--target` of
    the command-line `ablation` tool) now accept a character string that points
    to a file containing a configuration that will be read with
diff --git a/R/parameters.R b/R/parameters.R
index bff87997..fb3b7fce 100644
--- a/R/parameters.R
+++ b/R/parameters.R
@@ -337,6 +337,16 @@ ParameterSpace <- R6::R6Class("ParameterSpace", cloneable = TRUE, lock_class = T
       self$forbidden <- sapply(forbidden, compile_forbidden)
     }
 
+    # Optimize always TRUE conditions.
+    cond_names <- names(which(!unlist(lapply(self$conditions, is.logical))))
+    for (p in cond_names) {
+      deps <- self$depends[[p]]
+      # p depends on deps and they are both fixed and always active.
+      if (all(self$isFixed[deps]) && all(sapply(self$conditions[deps], isTRUE, USE.NAMES=FALSE))) {
+        self$conditions[[p]] <- eval(self$conditions[[p]], envir = self$domains[deps], enclos = NULL)
+      }
+    }
+    
     # Print the hierarchy vector:
     if (verbose >= 1L) {
       cat ("# --- Parameters Hierarchy ---\n")
diff --git a/tests/testthat/test-readParameters.R b/tests/testthat/test-readParameters.R
index bdf2d490..9b77dc09 100644
--- a/tests/testthat/test-readParameters.R
+++ b/tests/testthat/test-readParameters.R
@@ -1,5 +1,22 @@
 withr::with_output_sink("test-readParameters.Rout", {
 
+  test_that("optimize conditions", {
+    p <- readParameters(text='
+ROOT		"" c ("S")
+ROOT_T		"" c ("FIC")		| ROOT %in% c("S")
+ROOT_T_FIC.sum	"" r (-50.0, 50.0)	| ROOT_T %in% c("FIC")
+ROOT_T.FFI	"" c ("true")		| ROOT_T == "FIC"
+ROOT_T.im	"" c ("FFI", "FIC")	| ROOT == "S" & ROOT_T.FFI == "true"
+ROOT_E.FFI	"" c ("false")          | ROOT_T_FIC.sum < 0
+ROOT_E.FIC	"" i (0,100)            | ROOT_E.FFI == "false"
+')
+    expect_identical(p$conditions,
+      list(ROOT=TRUE, ROOT_T=TRUE, ROOT_T_FIC.sum=TRUE,
+        ROOT_T.FFI=TRUE, ROOT_T.im=TRUE,
+        ROOT_E.FFI=expression(ROOT_T_FIC.sum < 0),
+        ROOT_E.FIC=expression(ROOT_E.FFI == "false")))
+  })
+  
   test_that("error checking", {
 
     ref <- parametersNew(param_real(name = "tmp", lower = 0, upper=1,